Prenatal care is a key component of a healthy pregnancy. Regular prenatal care helps to identify and treat complications and promote healthy behaviors. Outcome data suggest that babies born to mothers who do not receive prenatal care are three times more likely to be of low birth weight, and five times more likely to die, compared with babies born to mothers who receive prenatal care.US Department of Health and Human Services: prenatal care fact sheet In addition to medical care, prenatal care includes counseling and education.[1] This topic provides an overview for the prenatal management of healthy pregnant women with singleton pregnancies.
Overview
Introduction
Preconception care
Ideally, prenatal care begins before conception. Preconception care has been defined as a set of interventions to identify and modify biomedical, behavioral, and psychosocial risks to a woman's health or pregnancy outcome through prevention and management. Preconception care should be considered not as a single visit, but as a continuum of care throughout a woman's reproductive life.[2] Because a significant proportion of pregnancies are unintended, the negative consequences of many behaviors, illnesses, and medications can affect fetal development early in pregnancy; often damage to the fetus occurs before a woman even realizes that she is pregnant. Thus, all routine healthcare encounters during a woman's reproductive years should include counseling on medical care and healthy behaviors to optimize pregnancy outcome.[2] [3] For example, healthy women should begin folic acid supplementation (400-800 micrograms/day), ideally at least 3 months before conception and continue until at least 12 weeks' gestation.[2] [3] [4] [5] [6]
Factors affecting pregnancy outcome should include consideration of age, family history, genetic history, nutritional status, folic acid intake, environmental and occupational exposures, and teratogens. A history of illicit substance use, tobacco and alcohol consumption, medical conditions, medication, immunization status, risk factors for sexually transmitted infections (STIs), psychosocial concerns (depression, domestic violence), and pregnancy spacing is required.[3]
Women with diabetes or chronic hypertension should be counseled on optimizing glycemic or blood pressure control, and pregnancy should be discouraged until control is achieved. Referral to a specialist for advice on the risks and benefits of treatment should be offered.[7] [8]
Women who are planning a pregnancy should be counseled regarding the relative risks and benefits of valproate use during pregnancy, and alternative therapeutic options should be considered. In the US, standard practice is that valproate and its analogs are only prescribed for the treatment of mental health problems in women who are planning a pregnancy, pregnant or considering breast-feeding if other alternative medications are not acceptable or not effective, or if the woman has responded only to valproate in the past.[9] In 2018, the European Medicines Agency recommended that valproate and its analogs are contraindicated during pregnancy because of the risk of congenital malformations and developmental problems in the infant/child.[10] In both Europe and the US, valproate and its analogs must not be used in women or girls of childbearing potential unless there is a pregnancy prevention program in place and certain conditions are met.[11] [12]
Before becoming pregnant, women should have an up-to-date vaccination record. Women should avoid pregnancy for 1 month after receiving a live attenuated vaccine (e.g., rubella or varicella).CDC: guidelines for vaccinating pregnant womenCDC: adult immunization schedule by age
Prenatal care
Early and regular prenatal care is recommended to improve pregnancy outcomes. Recommendations include prenatal visits, nutritional care, education, and other patient-specific issues.[1]
Prenatal visits
- Traditional prenatal care includes a series of between 7 and 11 visits; however, the number of visits necessary for adequate care is disputed. Though limited data are available regarding the optimal frequency, timing, and content of visits, the number of prenatal care visits should be determined according to the needs and risk status of each woman and her fetus.[1] [13] In addition to scheduled routine visits, pregnant women should have access to unscheduled or emergency visits on a 24-hour basis.
- Prenatal care visits should be scheduled at appropriate intervals to ensure time-sensitive testing and screenings, administration of Rho(D) immune globulin, if needed, and monitoring for common complications.
- The typical frequency of visits in an uncomplicated pregnancy is as follows:
- Every 4 weeks for the first 28 weeks
- Every 2 to 3 weeks between 28 and 36 weeks
- Weekly after 36 weeks.
- More frequent visits may occur at the prenatal care provider's discretion or at a patient''s request. Typical visits include evaluation of blood pressure, weight, testing urine for protein levels, and checking the fetal heart rate. Psychosocial screening at least once each trimester may help to identify issues that may require further evaluation, intervention, or outside referral.
- In areas with limited resources, reduced-visit programs are associated with an increase in perinatal mortality compared with standard practice, although neonatal intensive care admissions may be reduced. Women also prefer the standard visits schedule. While fewer visits may be associated with lower costs, a standard visit schedule should be recommended to all patients.[14]
- It is recommended that pregnant women initiate prenatal care by 10 to 12 weeks' gestation.[15] The first prenatal visit should include a comprehensive history, laboratory work, and education about pregnancy health. Height and weight should be recorded to calculate body mass index (BMI), which provides information to determine weight gain guidelines. At the first prenatal visit, all pregnant women should also have a blood test to check complete blood count, ABO blood group, Rh D status, and the presence of erythrocyte antibodies.[13] [16]
- Screening for depression, which is common during pregnancy and in the first 12 months after delivery, may be beneficial, particularly in women with a history of major depression. This enables the recognition of patients that may benefit from targeted therapy. Undiagnosed and untreated psychiatric illness is a risk to both the mother and fetus.[17] [18] See Postpartum depression .
- During the first appointment, ensure there is time for a private, one-to-one discussion with the women and ask sensitively about potential exposure to domestic abuse (assaultive and/or coercive behavior).[13] [19] [20] Women in the military or women veterans have a significantly increased risk of exposure to interpersonal violence, including sexual assault or abuse, and intimate partner violence.[21]
- A comprehensive physical exam should be performed at the first or second visit. An initial exam will identify women with female genital mutilation/cutting (FGM/C). Because FGM/C may adversely affect birth outcomes and increase risk for obstetric complications, these patients may have special intrapartum care needs.[22]
- At the second visit, a review of laboratory results will promote further discussion of a management plan.
- Women who are due to give birth at age 35 years or older should be advised of the potential adverse outcomes for mother and baby, and counseled accordingly, and those due to give birth ages 40 years or older should be offered antepartum fetal surveillance because of the increased risk of stillbirth.[23]
- If the woman has had a prior cesarean delivery, the risks and benefits of a trial of labor versus repeat cesarean delivery should be reviewed.[24] Candidacy for a trial of labor after cesarean should also be considered.
- The American College of Obstetricians and Gynecologists (ACOG) and the Centers for Disease Control and Prevention (CDC) recommend that adults receive an annual influenza vaccine and women who are or will be pregnant through the influenza season (October through May) undergo (inactivated or recombinant) influenza vaccination as soon as it is available.[25] Those women who are pregnant in the respiratory syncytial virus (RSV) season (September through January) are also recommended to have a single dose of the maternal RSV vaccine between 32 and 36 weeks of gestation, to protect infants ages <6 months against RSV-associated lower respiratory tract infections.[26] [27] ACOG and the CDC additionally recommend tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination for pregnant women, as early as possible between 27 and 36 weeks of gestation to maximize passive antibody transfer to the baby.[28] CDC: adult immunization schedule by age
- Appropriate fetal growth can be screened by measuring fundal height (symphysis to uterine fundus) from 24 to 38 weeks' gestation.[35] Fundal height in centimeters is approximately equal to the gestational age in weeks. Discrepancies of >3 cm should prompt ultrasound evaluation of amniotic fluid index and fetal growth.[36] The prenatal care provider should keep in mind that fundal height measurements can be influenced by numerous factors, including maternal size, bladder filling, uterine fibroids, multiple gestations, and fetal presentation.[35] [37]
- Mothers are questioned regarding pain, fetal movement, contraction frequency, vaginal bleeding, loss of fluid or discharge, other symptoms of preterm labor, and preeclampsia symptoms at appropriate gestation intervals, in addition to any other patient-provided complaints or concerns.[13]
- Structured records assist in ensuring comprehensive, evidence-based care.[38]
Nutritional counseling
- Nutrition education should focus on a well-balanced, varied, nutritional food plan consistent with the patient's food preferences. Obstetric care providers should calculate a woman's BMI at the first prenatal visit. Using BMI as a guideline, appropriate weight gain should be discussed.[39] [40] [41]
- Weight gain and caloric intake recommendations are higher for women pregnant with twins or higher-order multiple gestations. The daily recommended caloric intake for women with a normal BMI, who are pregnant with twins, is 40-45 kcal/kg daily (18-20 kcal/lb).[45] Women with multiple gestations have a higher incidence of anemia, compared with those who have singleton pregnancies, and so a blood test should be performed at 20 to 24 weeks to determine whether they need early supplementation with iron or folic acid.[46] Additional calcium, magnesium, and zinc supplementation may also be required for patients carrying multiple gestations over routine prenatal vitamin intake.
- Gestational weight gain greater than or less than the Institute of Medicine guidelines appears to be associated with higher risk of some adverse maternal and newborn outcomes.[47]
- Diet and physical activity-based interventions in pregnancy are beneficial and can reduce gestational weight gain, as well as the rate of cesarean delivery.[48]
- The Food and Drug Administration has made specific recommendations about fish intake for women of childbearing age.FDA: eating fish - what pregnant women and parents should know
- Listeriosis is a bacterial illness that can be particularly harmful to pregnant women, possibly resulting in miscarriage or stillbirth. To prevent listeriosis, pregnant women should avoid unpasteurized milk, soft cheeses, raw sprouts, some types of cold smoked fish, and some types of pâté.[3] [49] Additionally, pregnant women can reduce their risk of salmonella infection by avoiding raw or partially cooked eggs or food that may contain them (e.g., mayonnaise) and raw or partially cooked meat, especially poultry.
- Daily prenatal vitamins containing folate (400-800 micrograms/day) are recommended as tolerated throughout pregnancy, and at least through the first 3 months of pregnancy.[3] Ideally, women should start folate supplementation 12 weeks prior to conception.[6] Selected presentations, such as a prior pregnancy complicated by fetal neural tube defect, require higher-dose folate intake of 4 mg/day.[50] When started preconceptually and continued through pregnancy, folic acid supplementation may reduce risk of small-for-gestational-age neonates at birth.[51]
- Preterm birth is associated with lower levels of omega-3 fatty acid docosahexaeonoic acid (DHA), which has an important role in neurodevelopment. While observational data suggest that DHA supplementation has a beneficial effect on pediatric neurodevelopmental outcomes, randomized controlled trials have yielded conflicting results.[52] [53] There is insufficient evidence to support DHA supplementation to prevent preterm birth.[54] There is also no evidence that such supplementation reduces the risk of preeclampsia or gestational diabetes mellitus.[55]
- Vitamin C and E supplementation during pregnancy does not prevent preeclampsia.[56] While it may potentially have some benefit for the prevention of placental abruption and preterm premature rupture of membranes (PPROM), vitamin C alone or in combination with other supplements is unproven to reduce risk of fetal or neonatal death, poor fetal growth, preeclampsia, or preterm birth.[57]
- Moderate caffeine intake does not seem to have negative effects on pregnancy; however, caffeine intake should be limited to <200 mg daily.[58]
- Alcohol consumption is contraindicated in pregnancy. In the UK, Department of Health guidelines recommend that for pregnant women and women planning a pregnancy, the safest approach is not to drink alcohol at all, to keep risks to the baby to a minimum.[59] In the US there are no accepted guidelines regarding an acceptable alcohol intake in pregnancy. Prenatal drinking poses potentially serious consequences to both mother and fetus. Brief standardized screening questionnaires (Tolerance, Annoyance, Cut down, Eye opener [T-ACE], Alcohol Use Disorders Identification Test [AUDIT-C], Tolerance, Worried, Eye-opener, Amnesia, Cut down [TWEAK]) show promise as screening tools to identify risk drinking in pregnant women, although further investigation is required.[60]
Education
- Education to promote maternal and fetal health and safety is a significant component of prenatal care.
- At every prenatal appointment the women should be asked about their general health and wellbeing and healthy behaviors should be promoted, but also consider these specific issues:[13] [15]
- Substance misuse: women who regularly misuse recreational drugs, over-the-counter medications, prescription medications, volatile substances (such as solvents or inhalants) to an extent whereby physical dependence or harm is a risk to themselves and/or their unborn baby should be identified and treated.[63]
- Working: women with an uncomplicated pregnancy can typically continue working until the onset of labor. Women with medical complications or other pregnancy complications, may need to make adjustments.
- Air travel: women with uncomplicated pregnancies can fly safely until 36 weeks' gestation.ACOG: travel during pregnancy Pregnant women who are planning to fly should be informed about the increased risks of venous thromboembolism from the combination of pregnancy and venous stasis, and instructed to take appropriate precautions (support stockings, movement of lower extremities, hydration).[64]
- Exercise: women should be encouraged to continue or begin a moderate aerobic exercise program during pregnancy.[65] [66] Although the limited available randomized controlled trial data do not clearly support a benefit of exercise during pregnancy for the prevention of glucose intolerance or gestational diabetes mellitus, there may be other physical and psychological benefits derived from aerobic exercise in pregnancy.[67] Structured physical exercise has been demonstrated to significantly reduce the risk of delivering a macrosomic or large-for-gestational-age newborn without influencing the risk of having a small newborn.[68] When not otherwise contraindicated, physical exercise during pregnancy may reduce risk of cesarean delivery.[69] Potential risks from contact sports, high-impact sports, activities with risk of abdominal trauma, and scuba diving should also be discussed.
- Childbirth education: attendance in childbirth education classes may be considered. Classes teach expectant mothers about the relative risks and benefits of home versus hospital birth, labor and delivery, pain relief options, potential obstetric complications and procedures, normal newborn care, and postpartum adjustment.[70]
- Breast-feeding: throughout prenatal care, healthcare providers should provide information about the benefits of breast-feeding and breast-feeding support should be provided.[71]
- Miscellaneous: other educational issues to discuss during the antepartum period include dental care, nutrition, wearing a seat belt, minimal use of hot tubs or saunas, hazardous-chemical exposure, sleep position, sexual activity, postpartum contraception, and circumcision of male infants.
Routine testing
All women require a complete blood count (CBC), ABO blood group, Rhesus status, presence of erythrocyte antibodies, rubella status, hepatitis B screening, screening for STIs (syphilis, HIV, gonorrhea, and chlamydia), group B streptococcus (GBS) screening, urine dipstick and culture, blood pressure measurement, gestational diabetes screening, check of last cervical screening, and ultrasound.[13] [16][72] [73] [74][75] [76] [77][78] [79] Other investigations may be performed as indicated.
Additional tests to consider
Public health departments in certain states may require additional testing (e.g., more frequent syphilis screening).[82] In addition to routine laboratory tests, several other screening tests should also be considered, many of which are based on racial and ethnic background or family history.
STIs
- Women living in areas with high rates of STIs, or those with previous antepartum STI should be considered for repeat STI testing in the third trimester.[82] All women should be screened for syphilis at the first prenatal care visit, followed by universal rescreening during the third trimester and at birth.[79]
Vitamin D
- Routine screening of all pregnant women for vitamin D deficiency is not recommended; only those at high risk, including vegetarians, women with dark skin, those who live in northern latitudes, and those whose clothes leave little skin exposed, should be tested during pregnancy.[83] [84] Most women can ensure they receive enough vitamin D by taking prenatal supplements. If deficiency of vitamin D is identified during pregnancy, supplementation with 1000-2000 units/day of vitamin D is considered to be safe.[83] The Institute of Medicine has published a report on the dietary reference intakes for calcium and vitamin D advising an Estimated Average Requirement (EAR) for vitamin D of 400 IU/day (10 micrograms/day) with a Recommended Daily Allowance (RDA) of 600 IU/day (15 micrograms/day) during pregnancy.[85] Additionally, in the UK, updated UK-based National Institute for Health and Care Excellence (NICE) guidelines recommend vitamin D supplementation (10 micrograms/day) during pregnancy and while breastfeeding.[86]
Thyroid function tests
- Universal screening for subclinical hypothyroidism is controversial. Although several major societies favor routine screening in women who are pregnant or planning pregnancy, ACOG maintains that data are insufficient to warrant routine screening and continues to recommend testing in symptomatic women and those with a personal or family history of thyroid disease or other medical conditions associated with thyroid disease, such as type 1 diabetes.[87] To date, evidence does not support treatment of subclinical hypothyroidism as an intervention to improve pregnancy outcomes or neurocognitive function in neonates.[87] [88] [89]
Carrier screening
Ideally, genetic counseling should be performed before carrier screening.[90] ACOG recommends that all patients who are considering pregnancy or already pregnant are offered screening/tests for:[91]
- Cystic fibrosis
- Spinal muscular atrophy
- Complete blood count and screening for thalassemias and hemoglobinopathies.
Hemoglobin electrophoresis should be performed in addition to a complete blood count if hemoglobinopathy is suspected based on African, Mediterranean, Middle Eastern, Southeast Asian, or West Indian ethnicity.[90]
In the US, ACOG recommends universal testing for hemoglobinopathy traits in people planning pregnancy or at the first prenatal visit if no previous results are available.[92]
- Tay-Sachs disease (Ashkenazi Jews, French Canadians, Cajuns)
- Screening panels that detect mutations associated with disorders that commonly occur in Ashkenazi Jewish populations: Bloom syndrome, Canavan disease, cystic fibrosis, familial dysautonomia, Fanconi anemia group C, Gaucher disease, glycogen storage disease type 1a, maple syrup urine disease types 1A and 1B, mucolipidosis IV, Niemann-Pick disease type A, and Tay-Sachs disease.
Additional testing can be considered depending upon familial history, or on patient and physician preference:
- Fragile X syndrome for women with a family history of fragile X-related disorders or intellectual disability suggestive of fragile X syndrome, or women with a personal history of ovarian insufficiency; additional screening may be indicated based on family history or ancestry[91]
- Hemochromatosis for people of Celtic ancestry (especially if a positive family history exists)
- Duchenne muscular dystrophy.
Expanded carrier screening represents an alternative approach in which a large number of conditions are screened for simultaneously, and modern products can screen for as many as several hundred conditions. This approach is gaining in popularity due to its efficiency and cost value.[91]
Last updated
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