Ideally, patients planning to become pregnant and their partners should see an obstetric clinician for a preconception visit. At the visit, the clinician reviews general preventive measures available prior to pregnancy. The clinician also reviews the medical, obstetric, and family histories of both the patient and partner (or the donor, if donor sperm will be used and medical history of the donor is available). The clinician advises the patient about managing chronic diseases or medications or receiving vaccinations prior to pregnancy. The patient and partner are referred to genetic counseling, if appropriate.
1). Folate reduces risk of neural tube defects. If women have had a fetus or infant with a neural tube defect, the recommended daily dose is 4000 mcg (4 mg).
Once pregnant, women should have routine prenatal care to monitor the pregnancy and detect or prevent maternal or fetal complications. Also, visits every 1 to 4 weeks are required to monitor for and evaluate symptoms and signs of illness.
Specific obstetric disorders and nonobstetric disorders in pregnant women are discussed elsewhere in THE MANUAL.
The initial routine prenatal visit should occur between 6 and 8 weeks gestation.
Follow-up visits usually occur at:
About 4-week intervals until 28 weeks
2-week intervals from 28 to 36 weeks
Weekly from 36 weeks to delivery
Prenatal visits may be scheduled more frequently if there is a high risk of obstetric complications.
Prenatal care includes:
Screening and management of general medical disorders, infectious diseases, and psychiatric disorders
Screening for social determinants of health
Discussion of previous history of obstetric disorders (eg, gestational diabetes, preeclampsia, preterm birth)
Offering screening for fetal chromosomal disorders
Taking measures to reduce fetal and maternal risks
Monitoring for new maternal disease or obstetric complications
Monitoring fetal growth and development
Health promotion and patient education
General reference
History Taking in the Obstetric Patient
During the initial visit, clinicians should obtain a full medical history, including:
Obstetric history, with the outcome of all previous pregnancies, including maternal and fetal complications (eg, gestational diabetes, preeclampsia, congenital malformations, stillbirth)
Medical history, including surgical and psychiatric history
Family history, to identify any potential genetic disorders
Medications (including over-the-counter), supplements, illicit drug use, and potential toxic exposures
Social determinants of health
At the initial and subsequent visits, patients should be asked about symptoms of potential pregnancy complications (eg, vaginal bleeding, leakage of fluid, pelvic or abdominal pain, headache, changes in vision, edema of face or fingers, changes in frequency or intensity of fetal movement).
Gravidity and parity
The basic obstetric history is documented in a specific format, noting gravidity and parity.
Gravidity (G) is the number of confirmed pregnancies; a gravida is a term for a person who has had at least 1 pregnancy.
Parity (P) is the number of deliveries at ≥ 20 weeks of gestation. The numbers for parity are recorded along with other pregnancy outcomes:
Term deliveries (≥ 37 weeks)
Preterm deliveries (≥ 20 and < 37 weeks)
Abortions (including spontaneous pregnancy losses at < 20 weeks, induced abortions, ectopic pregnancies, or molar pregnancies)
Living children
Multifetal gestation is counted as 1 pregnancy in terms of gravidity and for all parity numbers, with the exception of living children (eg, for a woman who has had a singleton pregnancy and a twins pregnancy and all children are living, this is noted as 3).
In this documentation format, the numbers are recorded as:
G (gravidity number) P (parity number, noted as 4 numbers for term pregnancies, preterm pregnancies, abortions, and living children)
For example, the history of a patient who has had 1 term delivery, 1 set of twins born at 32 weeks, 1 spontaneous abortion, and 1 ectopic pregnancy is documented as G4 P1-1-2-3.
Physical Examination of the Obstetric Patient
A full general examination, including blood pressure (BP), height, and weight, is done first. BP and weight should be measured at each prenatal visit. A urine specimen is collected and checked with a dipstick for protein and findings consistent with infection.
In the initial obstetric examination, a complete pelvic examination is done to:
Estimate the gestational age based on uterine size
Check for uterine abnormalities (eg, leiomyoma) or tenderness
Check for lesions, discharge, or bleeding
Obtain cervical samples for testing
Pelvic examination is usually repeated only if symptoms (eg, vaginal bleeding or discharge, pelvic pain) are present. Starting at about 37 weeks, a sterile cervical digital examination may be done to check for cervical dilation and effacement.
Gestational age can be estimated on physical examination, although these estimates are imprecise and estimated delivery date should be determined based on last menstrual period and ultrasound measurements. The usual approach to is as follows:
< 12 weeks: Gestational age is estimated based on uterine size on bimanual pelvic examination. Traditionally, a general guide is that a 6-week pregnant uterus feels like a small orange, 8-week like a large orange, and 12-week like a grapefruit (1); precision may improve with clinical experience.
12 weeks: Uterine fundus is palpable at the level of the pubic symphysis.
16 weeks: Uterine fundus is at the midpoint between the level of the pubic symphysis and umbilicus.
20 weeks: Uterine fundus is at the level of the umbilicus.
> 20 weeks: Measurement from pubic symphysis to fundus in centimeters approximately correlates with gestational age.
Physical examination to estimate gestational age is not accurate if there are reasons for additional uterine enlargement, such as uterine leiomyoma or multiple gestation.
In late third trimester, palpation of the fetus through the abdomen is used to assess the fetal lie and estimate fetal weight (see figure Leopold Maneuver).
Traditionally, clinical pelvimetry was performed to estimate pelvic capacity and describe pelvic type (gynecoid, android, anthropoid, or platypelloid), with the aim of predicting need for operative vaginal delivery or cesarean delivery. This was based on measurements of the pelvic inlet by pelvic examination, radiography, CT, or MRI. However, clinical pelvimetry is rarely used in current clinical practice because it has not be shown to be more effective than a trial of labor at predicting mode of delivery (2).
Fetal heart rate is measured at each visit.
Physical examination reference
1. Margulies R, Miller L. Fruit size as a model for teaching first trimester uterine sizing in bimanual examination. Obstet Gynecol. 2001;98(2):341-344. doi:10.1016/s0029-7844(01)01406-5
2. Pattinson RC, Cuthbert A, Vannevel V: Pelvimetry for fetal cephalic presentations at or near term for deciding on mode of delivery. Cochrane Database Syst Rev. 2017;3(3):CD000161. Published 2017 Mar 30. doi:10.1002/14651858.CD000161.pub2
Symptoms and Signs of Pregnancy
Pregnancy may cause breasts to enlarge and feel mildly tender because of increased levels of estrogen (primarily) and progesterone, similar to premenstrual breast enlargement.
Nausea and vomiting may occur because of increased secretion of estrogenConception and Prenatal Development). The corpus luteum in the ovary, stimulated by beta-hCG, continues secreting large amounts of estrogen and progesterone to maintain the pregnancy. Many women become fatigued at this time, and a few women notice abdominal bloating very early.
Women usually begin to feel fetal movement between 16 and 20 weeks.
During late pregnancy, lower-extremity edema and varicose veins are common; the main cause is compression of the inferior vena cava by the enlarged uterus.
Diagnosis of Pregnancy
Urine or serum beta-hCG test
Usually urine and occasionally blood tests are used to confirm or exclude pregnancy; results are typically accurate several days before a missed menstrual period and often as early as several days after conception.
Pregnancy may also be confirmed with other findings, including:
Presence of a gestational sac in the uterus, typically visible on ultrasound at about 4 to 5 weeks and typically corresponding to a serum beta-hCG level of about 1500 mIU/mL (a yolk sac can usually be seen in the gestational sac by 5 weeks)
Fetal heart motion visualized on ultrasound as early as 5 to 6 weeks
Fetal heart sounds, heard with a handheld Doppler ultrasound device, as early as 8 to 10 weeks if the uterus is accessible abdominally
Fetal movements felt by the examining physician after 20 weeks
Estimated Date of Delivery in Pregnancy
The estimated date of delivery (EDD) is based on the last menstrual period (LMP). One way to calculate the EDD is to subtract 3 months from the LMP and add 7 days (Naegele's rule). Other methods are:
The date of conception + 266 days
The last menstrual period (LMP) + 280 days (40 weeks) for women with regular, 28-day menstrual cycles
The LMP + 280 days + (cycle length – 28 days) for women with regular menstrual cycles other than 28 days duration
Delivery up to 3 weeks earlier or 2 weeks later than the estimated date is considered normal. Delivery before 37 weeks gestation is considered preterm; delivery after 42 weeks gestation is considered postterm.
When periods are regular, the menstrual history is a relatively reliable method of determining EDD. When other information is lacking, first trimester ultrasound provides the most accurate estimate of gestational age. When the date of conception is unknown and menstrual cycles are irregular or information about them is not available, ultrasound may be the sole source of the EDD.
If there is uncertainty about menstrual dating, the gestational age based on the last menstrual period and based on the first fetal ultrasound in the current pregnancy are compared. If these age estimates are inconsistent, the EDD (and, thus, the estimated gestational age) may be changed, depending on the number of weeks and the degree of inconsistency. The American College of Obstetricians and Gynecologists (ACOG) (see Methods for Estimating Due Date) recommends using the date based on ultrasonographic measurements if it differs from the menstrual date by:
At ≥ 8 6/7 weeks of gestation: > 5 days
At 9 to 15 6/7 weeks of gestation: > 7 days
At 16 to 21 6/7 weeks of gestation: > 10 days
At 22 to 27 6/7 weeks of gestation: > 14 days
At ≥ 28 weeks of gestation: > 21 days
Reconciling the menstrual and ultrasonographic dates is done only after the first ultrasound in the current pregnancy—EDD is not changed based on subsequent ultrasounds. Because ultrasonographic estimates are less accurate later in pregnancy, second and third trimester ultrasonographic results should rarely be used to change estimated gestational age, and, if changing the estimated date of delivery is considered, a specialist in fetal ultrasonography should be consulted.
Testing in the Obstetric Patient
Laboratory testing
Prenatal evaluation involves blood tests, urine tests, cervical specimens, ultrasound, and sometimes other tests. Initial laboratory evaluation is thorough; some tests are repeated during follow-up visits (see table Routine Prenatal Evaluation Schedule).
Routine Prenatal Evaluation Schedule
Examination or Test | Initial Visit (usually first trimester) | Every Visit | Second Trimester | Third Trimester |
|---|---|---|---|---|
X | ||||
General physical examination | Complete general physical examination | Evaluate fetal growth by checking fundal height (starting at 12 weeks in a singleton pregnancy, when fundus can be palpated above the pubic symphysis) | At 20 weeks in a singleton pregnancy, fundal height should be at the level of the umbilicus | Abdominal examination for fetal lie and estimated weight (starting at approximately 36 weeks) |
Pelvic examination | Complete pelvic examination | Digital cervical examination (if indicated, starting > 36 weeks) | ||
Papanicolaou (Pap) test (if patient is due for cervical cancer screening) | X | |||
Weight | X | X | ||
Blood pressure | X | X | ||
Urine dipstick for protein | X | X | ||
Fetal heart rate measurement (usually with hand-held Doppler device) | X | X | ||
CBC | X | Repeat at 24 to 28 weeks | ||
Blood type and screen for alloantibodies | X | Repeat in patients with Rh-negative blood type at 28 weeks* | ||
Rubella and varicella immunity | X† | |||
Hepatitis C | X | |||
X | Repeat in high-risk patients at 24 to 28 weeks | |||
Human immunodeficiency virus (HIV) | X | Repeat in high-risk patients at 28 to 36 weeks | ||
Syphilis | X | Repeat in high-risk patients at 28 to 36 weeks | ||
Gonorrhea and chlamydia | X | Repeat in high-risk patients at 28 to 36 weeks | ||
Tuberculosis (if at risk) | X | |||
Urine culture | X | |||
Swab of vagina and rectum for Group B beta-hemolytic streptococcus (GBS) colonization | At 36 to 37 weeks‡ | |||
Fasting plasma glucose or random plasma glucose | Oral glucose tolerance test to screen for gestational diabetes at 24 to 28 weeks | |||
HbA1C | Only in patients at increased risk of undiagnosed type 2 diabetes | |||
Pelvic ultrasound | Often done in first trimester if needed to estimate gestational age | Anatomy survey at 18 to 22 weeks | ||
Counseling about testing for genetic and anatomic abnormalities; if desired, genetic carrier testing of parents is done prior to pregnancy or in the first trimester, and noninvasive (blood tests and/or ultrasound) and/or diagnostic testing (chorionic villous sampling or amniocentesis) are done in the first and/or second trimester | X | |||
Testing for neural tube defects, if desired | Ultrasound Maternal serum alpha-fetoprotein (MSAFP), at 16 to 18 weeks | |||
Screening for anxiety and depression (screen more frequently if indicated) | X | X | ||
Screening for intimate partner violence (screen more frequently if indicated) | X | |||
* To prevent alloimmunization, pregnant patients with a Rh-negative blood type should receive anti-D immune globulin injection at either 28 weeks or 28 and 34 weeks. | ||||
† Rubella and varicella titers are measured unless women have documentation of vaccination or previous infection, thus confirming immunity. | ||||
‡ Not required in patients with GBS bacteriuria earlier in the current pregnancy or those who gave birth to a previous neonate with invasive GBS disease (intrapartum antibiotic prophylaxis is already recommended for these patients, so a third trimester vaginal-rectal swab is not necessary). | ||||
CBC = complete blood count | ||||
Routine testing evaluates for anemia, proteinuria, and infectious diseases that may affect fetal development or maternal health. Proteinuria before 20 weeks gestation suggests kidney disease. Proteinuria after 20 weeks gestation may indicate preeclampsia. Patients with any colony count of Group B streptococcus (GBS) in a urine culture at any time during pregnancy (which suggests heavy vaginal–rectal colonization) should be given antibiotic prophylaxis at the time of delivery (1).
Blood type and alloantibodies are checked because women with Rh-negative blood are at risk of developing Rh(D) antibodies (if previously exposed to Rh-positive blood). If the father has Rh-positive blood, the fetus may also be Rh-positive, and maternal anti-Rh(D) antibodies can cross the placenta and cause hemolytic disease of the fetus. Rh(D) antibody levels should be measured in pregnant women at the initial prenatal visit and, in those with Rh-negative blood, again at about 28 weeks.
Generally, women are routinely screened for gestational diabetes between 24 and 28 weeks using an oral glucose tolerance test. However, if women have significant risk factors for undiagnosed type 2 diabetes, they are screened during the first trimester with a random or fasting serum glucose and HbA1C. These risk factors include a combination of obesity and one or more of the following risk factors (2):
Physical inactivity
First-degree relative with diabetes
Race or ethnicity associated with increased risk (eg, African American, Latino, Native American, Asian American, Pacific Islander)
Gestational diabetes or a macrosomic neonate (weight ≥ 4,000 g) in a previous pregnancy
Hypertension (140/90 mmHg or on therapy for hypertension)
High-density lipoprotein cholesterol level < 35 mg/dL (0.90 mmol/L) or a triglyceride level > 250 mg/dL (2.82 mmol/L)
HbA1C ≥ 5.7%, impaired glucose tolerance, or impaired fasting glucose on previous testing
2, acanthosis nigricans)
History of cardiovascular disease
If the first-trimester test is normal, patients are screened for gestational diabetes at 24 to 28 weeks.
If either potential parent has a known or suspected genetic abnormality, the couple should be referred for genetic counseling and testing. Pregnant patients should also be counseled about options for noninvasive screening or diagnostic testing for fetal aneuploidy. The American College of Obstetricians and Gynecologists recommends that all women be offered diagnostic testing, irrespective of baseline risk or maternal age, including non-invasive prenatal testing (NIPT) or cell free DNA testing (3).
Blood tests to screen for or monitor thyroid disorders (measurement of thyroid-stimulating hormone [TSH]) are done in women with one or more of the following (4):
Symptoms or other reasons for clinical suspicion of disease
Thyroid disease or family history of thyroid disease
Type 1 diabetes
Evaluation for other disorders (eg, lead level, measles, bacterial vaginosis, Zika virus infection, Chagas disease, and others) are done depending on medical history, risk factors, symptoms, and recent exposures.
Ultrasonography
Most obstetricians recommend at least one ultrasound examination during each pregnancy, ideally between 16 and 20 weeks. Earlier ultrasound may be done if there is uncertainty about the estimated delivery date (EDD) or if a patient has symptoms (eg, vaginal bleeding, pelvic pain).
Specific indications for ultrasound examination include:
Detection of multifetal gestation, hydatidiform mole, ectopic pregnancy
Investigation of fetal abnormalities (eg, indicated by abnormal results of noninvasive maternal screening tests or uterus size not consistent with estimated gestational age)
Nuchal translucency measurement as a component of noninvasive aneuploidy screening tests
Detailed assessment of fetal anatomy (usually at about 16 to 20 weeks)
Possibly fetal echocardiography at 20 weeks if risk of congenital heart defects is high (eg, in women who have type 1 diabetes or have had a child with a congenital heart defect)
Determination of placental location, polyhydramnios, or oligohydramnios
Determination of fetal position and size
Ultrasound is also used for needle guidance during chorionic villus sampling, amniocentesis, and fetal transfusion.
If an ultrasound is needed during the first trimester (eg, to evaluate pain, bleeding, or viability of pregnancy), use of an endovaginal transducer maximizes diagnostic accuracy; evidence of an intrauterine pregnancy (gestational sac or fetal pole) can be seen as early as 4 to 5 weeks and is seen at 7 to 8 weeks in > 95% of cases. Fetal movements and heart motion can be directly observed on ultrasound as early as 5 to 6 weeks.
Other imaging
Medically necessary radiographs or other imaging should not be postponed because of pregnancy. However, elective abdominal radiographs are postponed until after pregnancy.
The risk of exposure to the fetus of ionizing radiation from imaging studies depends upon gestational age and radiation dose. The effects and threshold dose for various gestational ages include (5):
2 to 3 weeks (fertilization to implantation): Death of embryo or no effect (50 to100 milligray [mGy])
4 to 10 weeks (during organogenesis): Congenital anomalies (200 mGy); growth restriction (200 to 250 mGy)
8 to 15 weeks: High risk of severe intellectual disability (60 to 310 mGy); microcephaly (200 mGy)
16 to 25 weeks: Low risk of severe intellectual disability (250 to 280 mGy)
Imaging studies can be categorized by dose of radiation to the fetus (5):
Very low dose (< 0.1 mGy): Radiographs or CT of the head and neck or extremities; chest radiographs
Low to moderate dose (0.1 to 10 mGy): Radiographs of the abdomen or spine; intravenous pyelography; double-contrast barium enema; chest CT; nuclear medicine scans (eg, low-dose scintigraphy or angiography)
Higher dose (10 to 50 mGy): Abdominal or pelvic CT
Thus, reproductive-aged women should be asked about the possibility of a current pregnancy (and a pregnancy test should be done, if indicated) before radiographs or CTs are performed. Abdominal or pelvic CT is sometimes used during pregnancy if it is the standard and most effective imaging modality for a particular diagnostic indication. In this case, the patient should be counseled about risks and benefits and informed consent should be obtained.
MRI does not emit radiation and may be used throughout pregnancy without concern for pregnancy-associated risks.
In addition, contrast agents are often used to enhance imaging modalities. Contrast agents for CT imaging have not been associated with teratogenic effects. Conversely, gadolinium-containing contrast commonly used for MRI imaging is controversial based on animal model data suggesting teratogenicity, but this has not been confirmed in humans. Thus, contrast use in MRI is reserved for specific situations in which clinical management may be changed or the condition is considered life threatening to the pregnant individual (5).
Testing references
1. American College of Obstetricians and Gynecologists (ACOG): Prevention of Group B Streptococcal Early-Onset Disease in Newborns: ACOG Committee Opinion, Number 797 [published correction appears in Obstet Gynecol. 2020 Apr;135(4):978-979]. Obstet Gynecol. 2020;135(2):e51-e72. doi:10.1097/AOG.0000000000003668
2. ACOG Committee on Practice Bulletins: ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol. 2018;131(2):e49-e64. doi:10.1097/AOG.0000000000002501
3. ACOG Committee on Practice Bulletins—Obstetrics; Committee on Genetics; Society for Maternal-Fetal Medicine: Screening for Fetal Chromosomal Abnormalities: ACOG Practice Bulletin, Number 226. Obstet Gynecol. 2020;136(4):e48-e69. doi:10.1097/AOG.0000000000004084
4. ACOG Committee on Practice Bulletins—Obstetrics: Thyroid Disease in Pregnancy: ACOG Practice Bulletin, Number 223. Obstet Gynecol. 2020;135(6):e261-e274. doi:10.1097/AOG.0000000000003893
5. ACOG Committee on Obstetric Practice: Opinion No. 723: Guidelines for Diagnostic Imaging During Pregnancy and Lactation [published correction appears in Obstet Gynecol. 2018 Sep; 132(3):786. doi: 10.1097/AOG.0000000000002858]. Obstet Gynecol. 2017 (reaffirmed 2021);130(4):e210-e216. doi:10.1097/AOG.0000000000002355
Management of the Obstetric Patient
Preexisting maternal disease or risk factors for obstetric complications or maternal or fetal issues that present during pregnancy are managed, as appropriate. Prenatal care also includes counseling about health promotion and anticipatory guidance to prepare patients for labor, delivery, and newborn care. Couples are encouraged to attend childbirth classes.
High-risk pregnancies require close monitoring, specialized care, and a multidisciplinary medical team, and sometimes referral to a perinatal center. Perinatal centers offer many specialty and subspecialty services provided by maternal, fetal, and neonatal specialists. Close monitoring throughout the pregnancy may involve management of chronic diseases and increased frequency of prenatal visits, blood tests, and ultrasonography and other types of fetal monitoring. Communication with the pregnant woman and her family is essential to involve the patient in shared decision-making, develop a care plan, and provide emotional support.
Symptoms requiring evaluation
Patients are counseled about normal pregnancy changes, sensations, and fetal movement, diet, weight gain, mental health, recommended preventive measures, and health promotion. They are also counseled about concerning symptoms for which they should contact their obstetric clinician, including vaginal bleeding, persistent uterine contractions, leakage of fluid, fever, dysuria, urinary frequency, urinary urgency, decreased fetal movement, severe persistent pain (headache, pain in the pelvic, abdomen, back, calves), faintness or dizziness, shortness of breath, edema of the face, hands, or asymmetric edema of the calves, and visual changes.
Multiparous women with a history of rapid labor should notify the physician at the first symptom of labor.
Diet and supplements
To provide nutrition for the fetus, the average number of additional calories pregnant patients who begin pregnancy with a body mass index (BMI) in the normal range require varies by trimester: first trimester, no additional calories; second trimester, approximately 340 kcal extra daily; third trimester, approximately 450 kcal extra daily. See Eat Healthy During Pregnancy: Quick Tips. Most calories should come from protein. If maternal weight gain is excessive (> 1.4 kg/month during the early months) or inadequate (< 0.9 kg/month), diet must be modified further.
1). Women who have had a fetus with spina bifida should take 4 mg once a day, starting 3 months before conception and continuing through 12 weeks of gestation (2).
Most prenatal vitamins contain the recommended daily allowance of ferrous iron during pregnancy (27 mg) (3). In patients with iron deficiency anemia, a higher dose is needed (eg, 325 mg ferrous sulfate [65 mg elemental iron]). Iron is usually taken daily but may be taken every other day if a patient has bothersome gastrointestinal effects, especially constipation.
Pregnant patients should also be counseled on safe food handling practices, including avoiding certain seafood with high mercury levels and foods with a high risk of contamination by Listeria, such as:
Raw or rare fish, shellfish, meat, poultry, or eggs
Unpasteurized juice, milk, or cheese
Lunch or deli meats, smoked seafood, and hot dogs (unless heated to a steaming hot temperature)
Prepared meat or seafood salads like ham salad, chicken salad, or tuna salad
Raw sprouts, including alfalfa, clover, radish, and mung bean sprouts
Weight gain
Women are counseled about exercise and diet and advised to follow the Institute of Medicine guidelines for weight gain, which are based on prepregnancy body mass index (BMI—see table Guidelines for Weight Gain During Pregnancy). Weight-loss dieting during pregnancy is not recommended, even for women with severe obesity.
Guidelines for Weight Gain During Pregnancy*
Prepregnancy Weight Category | BMI | Total Weight Gain† | Recommended Mean Weight Gain During the Second and Third Trimesters‡ |
|---|---|---|---|
Underweight | < 18.5 | 12.5–18 kg (28–40 lb) | 0.4 kg/week (1 lb/week) |
Normal weight | 18.5–24.9 | 11.5–16 kg (25–35 lb) | 0.4 kg/week (1 lb/week) |
Overweight (0.5–0.7) | 25.0–29.9 | 6.8–11.3 kg (15–25 lb) | 0.27 kg/week (0.6 lb/week) |
Obese (includes all classes) | ≥ 30.0 | 5–9 kg (11–20 lb) | 0.23 kg/week (0.5 lb/week) |
* Recommendations for weight gain are based on prepregnancy BMI. | |||
† For women with a twin pregnancy, provisional recommendations for total weight gain are as follows:
| |||
‡ A weight gain of 0.5–2 kg (1.1–4.4 lb) during the first trimester is assumed. | |||
BMI = body mass index (kg/m2). | |||
Adapted from Rasmussen KM, Yaktine AL, Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines, eds: Weight Gain During Pregnancy: Reexamining the Guidelines. Washington (DC): National Academies Press (US); 2009 and American College of Obstetricians and Gynecologists: ACOG Committee opinion no. 548: weight gain during pregnancy. Obstet Gynecol. 2013 (reaffirmed 2023);121(1):210-212. doi:10.1097/01.aog.0000425668.87506.4c). | |||
Physical activity
Exercise during pregnancy has minimal risks and has demonstrated benefits for most pregnant women, including maintenance or improvement of physical fitness, control of gestational weight gain, reduction in low back pain, and possibly a reduction in risk of developing gestational diabetes or preeclampsia (4). Moderate exercise is not a direct cause of any adverse pregnancy outcome; however, pregnant women may be at greater risk of injuries to joints, falling, and abdominal trauma. Abdominal trauma can result in placental abruption, which can lead to fetal morbidity or death.
Sexual activity can be continued throughout pregnancy unless vaginal bleeding, pelvic or vaginal pain, vaginal discharge, leakage of amniotic fluid, or uterine contractions occur.
Medications, substance use, and toxic exposures
Clinicians should review the patient's medications and nutritional supplements to address drug safety in pregnancy and determine if any medications or supplements need to be discontinued, adjusted, or changed.
Consuming caffeine in small amounts (eg, 1 cup of coffee a day) appears to pose little or no risk to the fetus.
Pregnant patients should not use alcohol, tobacco (and should avoid exposure to secondhand smoke), cannabis, or illicit drugs. Patients with substance use disorders should be managed by a multidisciplinary team with appropriate expertise, including an obstetrician, addiction specialist, and pediatrician.
Pregnant patients should also avoid the following:
Direct handling of cat litter (due to risk of toxoplasmosis)
Prolonged temperature elevation (eg, in a hot tub or sauna)
Exposure to people with active viral infections (eg, rubella, erythema infectiosum [fifth disease], varicella)
Exposure to toxic environmental agents during pregnancy has been associated with adverse reproductive and developmental health outcomes, including infertility, miscarriage, preterm birth, low birth weight, neurodevelopmental delay, and childhood cancer (5). The risk of adverse outcome depends on the toxin and extent of the exposure. Obstetric clinicians should include questions about environmental health as part of the medical history.
Patients should be advised to avoid or minimize exposure to specific agents, such as lead, pesticides, solvents, and phthalates. Personal care products used during pregnancy should have no phthalates, parabens, oxybenzone, or triclosan. Cosmetic and personal care products labeled "fragrance-free" are less likely to contain toxins than those labelled "unscented."
Immunizations
Vaccines during pregnancy are as effective in women who are pregnant as in those who are not.
Live-virus vaccines, such as those for rubella or varicella, should not be used during pregnancy.
The following vaccines are recommended for all or selected pregnant women by the American College of Obstetricians and Gynecologists (ACOG) (see ACOG: Maternal Immunization):
Influenza vaccine: All pregnant women during influenza season.
COVID-19 vaccine: People 5 years and older, including people who are pregnant, breastfeeding, trying to get pregnant, or might become pregnant in the future (see also Centers for Disease Control and Prevention (CDC): COVID-19 Vaccines While Pregnant or Breastfeeding)
Tetanus-diphtheria-pertussis (Tdap) vaccine: Pregnant patients during the third trimester (6)
Respiratory syncytial virus (RSV) vaccine: Pregnant patients between 32 0/7 and 36 6/7 weeks of gestation, using seasonal administration, to prevent RSV lower respiratory tract infection in infants (for most of the United States, RSV season occurs from September through January) (see CDC: Healthcare Providers: RSV Vaccination for Pregnant People and ACOG: Maternal Respiratory Syncytial Virus Vaccination)
Other vaccines should be reserved for situations in which the woman or fetus is at significant risk of exposure to a hazardous infection and/or are at increased risk of complications, and the risk of adverse effects from the vaccine is low. Pneumococcal vaccination is recommended for pregnant patients at increased risk of severe pneumococcal disease. Vaccinations for cholera, hepatitis A, hepatitis B, measles, mumps, plague, poliomyelitis, rabies, typhoid, and yellow fever may be given during pregnancy if risk of infection is substantial.
Prevention of perinatal complications
For pregnant patients with a Rh-negative blood type, Rho(D) immune globulin is given to prevent alloimmunization, which could result in hemolytic disease of the fetus and neonate. Rho(D) immune globulin is given at 28 weeks, before any episode or procedure that may cause fetal-maternal hemorrhage, and after delivery.
For pregnant patients with increased risk of preeclampsia
Psychosocial issues
Screening for depression and anxiety should be done at the first prenatal visit and repeated in third trimester and postpartum. Screening should also be done for intimate partner violence.
Patients should be asked about barriers to accessing care or that require support or accommodations (eg, physical or cognitive disabilities, language barriers, personal, family, social, religious, or financial issues). Clinicians should give patients information and help patients access available resources.
Travel
There is no absolute contraindication to travel at any time during pregnancy. Pregnant women should wear seat belts regardless of gestational age and type of vehicle.
Travel on airplanes is allowed by most airlines until 36 weeks gestation, because of the risk of going into labor and delivering during the flight.
During any kind of travel, pregnant women should stretch and straighten their legs and ankles periodically to prevent venous stasis and the possibility of thrombosis. For example, on long flights, they should walk or stretch every 2 to 3 hours. In some cases, clinicians may recommend thromboprophylaxis for prolonged travel.
Treatment references
1. US Preventive Services Task Force, Barry MJ, Nicholson WK, et alJAMA. 2023; 330(5):454-459. doi:10.1001/jama.2023.12876
2. American College of Obstetricians and Gynecologists' Committee on Practice Bulletins: Practice Bulletin, Number 187, Neural Tube Defects. Obstet Gynecol. 2017 (reaffirmed 2021);130(6):e279-e290. doi:10.1097/AOG.0000000000002412
3. American College of Obstetricians and Gynecologists' Committee on Practice Bulletins: Practice Bulletin, Number 233, Anemia in Pregnancy. Obstet Gynecol. 2021;138(2):e55-e64. doi:10.1097/AOG.0000000000004477
4. Syed H, Slayman T, Thoma KD: ACOG Committee Opinion No. 804: Physical activity and exercise during pregnancy and the postpartum period. 2020. PMID: 33481513. doi: 10.1097/AOG.0000000000004266
5. ACOG Committee on Obstetric Practice: Reducing Prenatal Exposure to Toxic Environmental Agents: ACOG Committee Opinion, Number 832. Obstet Gynecol. 2021;138(1):e40-e54. doi:10.1097/AOG.0000000000004449
6. Committee Opinion No. 718: Update on Immunization and Pregnancy: Tetanus, Diphtheria, and Pertussis Vaccination. Obstet Gynecol. 2017;130(3):e153-e157. doi:10.1097/AOG.0000000000002301
