CHAPTER 19: The Pregnant Woman
This chapter presents the history and physical examination of the healthy pregnant woman. Many of the techniques of examination are similar to those of the nonpregnant woman; however, the clinician must distinguish the changes of pregnancy from abnormal findings. This chapter reviews common anatomic and physiologic changes as they evolve throughout pregnancy, elements of the health history specific to the pregnant woman, recommendations for prenatal health promotion and counseling, and physical examination techniques specific to pregnancy (Figs. 19-1).
FIGURE 19-1 Support a healthy delivery.
Anatomy and Physiology
Physiologic Hormonal Changes
The hormonal changes of pregnancy alter many of the body systems. Because these normal but complex variations result in visible changes in anatomy, in this chapter, the physiologic changes of pregnancy precede the discussion of anatomy and are briefly summarized here.
▪ Estrogen promotes endometrial growth that supports the early embryo. It appears to stimulate marked enlargement of the pituitary gland (by up to 135%) and increased prolactin output from its anterior lobe, which readies breast tissue for lactation. Estrogen also contributes to the hypercoagulable state that puts pregnant women at four to five times higher risk for thromboembolic events, primarily in the venous system.
▪ Progesterone levels increase throughout pregnancy, leading to increased tidal volume and alveolar minute ventilation, though respiratory rate remains constant; respiratory alkalosis and subjective shortness of breath result from these changes. Lower esophageal sphincter tone resulting from rising levels of estradiol and progesterone contributes to gastroesophageal reflux. Progesterone relaxes tone in the ureters and bladder, causing hydronephrosis (in the right ureter more than the left) and an increased risk of bacteriuria.
▪ Human chorionic gonadotropin (HCG) has five variant subtypes. Two are produced by the placenta and support progesterone synthesis in the corpus luteum, stabilizing the endometrium and effectively preventing loss of the early embryo to menstruation. Serum and urine pregnancy assays test primarily for the two pregnancy-related HCG variants; three isoforms are produced by different cancers and the pituitary gland.
▪ Placental growth hormone influences fetal growth and the development of preeclampsia. Placental growth hormone and other hormones have been implicated in insulin resistance after midpregnancy and in gestational diabetes, which carries a lifetime risk of progressing to type 2 diabetes of up to 60%.,
▪ Thyroid function changes include an increase in thyroid-binding globulin due to rising levels of estrogen and stimulation of thyroid-stimulating hormone (TSH) receptors by HCG. This results in a slight increase, usually in the normal range, in serum concentrations of free T3 and T4, while serum TSH concentrations appropriately decrease. This transient apparent “hyperthyroidism” should be considered physiologic.
▪ Relaxin is secreted by the corpus luteum and placenta and is involved in the remodeling of reproductive tract connective tissue to facilitate delivery, increased renal hemodynamics, and increased serum osmolality. Despite its name, relaxin does not affect peripheral joint laxity during pregnancy. Weight gain, especially around the gravid uterus, and shifts in the center of gravity contribute to lumbar lordosis and other musculoskeletal strain.
▪ Erythropoietin increases during pregnancy, which raises erythrocyte mass. Plasma volume increases to a greater extent, causing relative hemodilution and physiologic anemia, which can protect against blood loss during birth. Cardiac output increases but systemic vascular resistance decreases, resulting in a net fall in blood pressure, especially during the second trimester and returning to normal by the third trimester.
▪ Basal metabolic rate increases 15% to 20% during pregnancy, increasing daily energy demands by an estimated 85, 285, and 475 kcal/d in the first, second, and third trimesters, respectively.
Changes in the breasts, abdomen, and urogenital tract are the most visible signs of pregnancy. Review the anatomy and physiology of these body systems in Chapter 10, Breasts and Axillae; Chapter 11, Abdomen; and Chapter 14, Female Genitalia.
The breasts become moderately enlarged due to hormonal stimulation that causes increased vascularity and glandular hyperplasia. By the third month of gestation, the breasts become more nodular. The nipples become larger and more erectile, with darker areolae and more pronounced Montgomery glands. The venous pattern over the breasts becomes visibly more prominent as pregnancy progresses. In the second and third trimesters, some women secrete colostrum, a thick, yellowish, nutrient-rich precursor to milk. Breast tenderness may make them more sensitive during examination.
Muscle cell hypertrophy, increases in fibrous and elastic tissue, and development of blood vessels and lymphatics all contribute to growth of the uterus. The uterus increases in weight from ∼70 g at conception to almost 1,100 g at delivery, when it accommodates from 5 to 20 L of fluid. In the first trimester, the uterus is confined to the pelvis and shaped like an inverted pear; it may retain its prior anteverted (forward-leaning), retroverted (backward-leaning), or retroflexed (backward-bent) position. By 12 to 14 weeks, the gravid uterus becomes externally palpable as it expands into a globular shape beyond the pelvic brim.
Beginning in the second trimester, the enlarging fetus pushes the uterus into an anteverted position that encroaches into the space usually occupied by the bladder, triggering frequent voiding. The intestines are displaced laterally and superiorly. The uterus stretches its own supporting ligaments, causing “round ligament pain” in the lower quadrants. Often, slight dextrorotation to accommodate the rectosigmoid structures on the left side of the pelvis leads to greater discomfort on the right side as well as increased right-sided hydronephrosis. Growth patterns of the gravid uterus are shown in Figure 19-4. Sagittal depictions of the gravid abdomen during each trimester appear in Figures 19-5 to 19-7.
FIGURE 19-4 Growth patterns of the uterine fundus by weeks of pregnancy.
FIGURE 19-5 First trimester.
FIGURE 19-6 Second trimester.
FIGURE 19-7 Third trimester.
Increased vascularity throughout the pelvis gives the vagina a bluish color, known as Chadwick sign. The vaginal walls appear deeply rugated due to thicker mucosa, loosening of connective tissue, and hypertrophy of smooth muscle cells. Normal vaginal secretions may become thick, white, and more profuse, known as leukorrhea of pregnancy. Increased glycogen stores in the vaginal epithelium give rise to a proliferation of Lactobacillus acidophilus, which lowers the vaginal pH. This acidification protects against some vaginal infections, but at the same time, increased glycogen may contribute to higher rates of vaginal candidiasis.
At ∼1 month after conception, the cervix softens and also turns bluish or cyanotic in color, reflecting the increased vascularity, edema, and glandular hyperplasia throughout the cervix. Hegar sign is the palpable softening of the cervical isthmus, the portion of the uterus that narrows into the cervix, illustrated in Figure 19-8. This cervical remodeling involves rearrangement of the cervical connective tissue that decreases collagen concentration and facilitates dilatation during delivery. Copious cervical secretions fill the cervical canal soon after conception with a tenacious mucus plug that protects the uterine environment from outside pathogens and is expelled as bloody show at delivery.
FIGURE 19-8 Hegar sign.
Early in pregnancy, the corpus luteum, which is the ovarian follicle that has discharged its ovum, may be prominent enough to be felt on the affected ovary as a small nodule; this disappears by midpregnancy.
As the skin over the abdomen stretches to accommodate the fetus, purplish striae gravidarum or “stretch marks” and a linea nigra, a brownish black pigmented vertical stripe along the midline skin, may appear. As tension on the abdominal wall increases with advancing pregnancy, the rectus abdominis muscles may separate at the midline, called diastasis recti. If diastasis is severe, especially in multiparous women, only a layer of skin, fascia, and peritoneum may cover the anterior uterine wall, and fetal parts may be palpable through this muscular gap.
|Missed periods (amenorrhea)||All||High levels of estrogen, progesterone, and HCG build up the endometrium and prevent menses, causing missed periods which are often the first noticeable sign of pregnancy.|
|Heartburn||All||Progesterone relaxes the lower esophageal sphincter, allowing gastric contents to reflux into the esophagus. The gravid uterus also exerts physical pressure against the stomach, contributing to reflux symptoms.1|
|Urinary frequency||All||Increases in blood volume and filtration rate through the kidneys result in increased urine production, while pressure from the gravid uterus reduces potential space for the bladder. Dysuria or suprapubic pain should be investigated for urinary tract infection.|
|Vaginal discharge||All||Asymptomatic milky white discharge, leukorrhea, results from increased secretions from vaginal and cervical epithelium due to vasocongestion and hormonal changes. Any foul-smelling or pruritic discharge should be investigated.|
|Constipation||All||Constipation results from slowed gastrointestinal transit due to hormonal changes, dehydration from nausea and vomiting, and the supplemental iron in prenatal vitamins.|
|Hemorrhoids||All||Hemorrhoids may be caused by constipation, decreased venous return from increasing pressure in the pelvis, compression by fetal parts, and changes in activity level during pregnancy.|
|Backache||All||Hormonally induced relaxation of the pelvic ligaments contributes to musculoskeletal aches. Lordosis required to balance the gravid uterus contributes to lower back strain. Breast enlargement may contribute to upper backaches.|
|Nausea and/or vomiting||First||This is poorly understood but appears to reflect hormonal changes, slowed gastrointestinal peristalsis, alterations in smell and taste, and sociocultural factors. Hyperemesis gravidarum is vomiting with weight loss of >5% of prepregnancy weight.|
|Breast tenderness/tingling||First||Pregnancy hormones stimulate the growth of breast tissue, which causes swelling and possible aching, tenderness, and tingling. Increased blood flow can make delicate veins more visible beneath the skin.|
|Fatigue||First/Third||Fatigue is related to the rapid change in energy requirements, sedative effects of progesterone, changes in body mechanics due to the gravid uterus, and sleep disturbance. Many women report increased energy and well-being during the second trimester.|
|Lower abdominal pain||Second||Rapid growth in the second trimester causes tension and stretching of the round ligaments that support the uterus, causing sharp or cramping pain with movement or position change.|
|Abdominal striae||Second or third||Stretching of the skin and tearing of the collagen in the dermis contribute to thin, usually pink, bands, or striae gravidarum (stretch marks). These may persist or fade over time after delivery.|
|Contractions||Third||Irregular and unpredictable uterine contractions (Braxton Hicks contractions) are rarely associated with labor. Contractions that become regular or painful should be evaluated for onset of labor.|
|Loss of mucus plug||Third||Passage of the mucus plug is common during labor but may occur prior to the onset of contractions. As long as there are no regular contractions, bleeding, or loss of fluid, loss of the mucus plug is unlikely to trigger the onset of labor.|
|Edema||Third||Decreased venous return, obstruction of lymphatic flow, and reduced plasma colloid oncotic pressure commonly cause lower extremity edema. However, sudden severe edema and hypertension may signal preeclampsia.|
The Health History
- Initial prenatal history
- Confirmation of pregnancy
- Symptoms of pregnancy
- Concerns and attitudes toward the pregnancy
- Current health and past clinical history
- Past obstetric history
- Risk factors for maternal and fetal health
- Family history of patient and father of the newborn
- Plans for breastfeeding
- Plans for postpartum contraception
- Determining gestational age and expected date of delivery
Prenatal care focuses on optimizing health and minimizing risk for the mother and fetus. The goals of the initial prenatal visit are to define the health status of the mother and fetus, confirm the pregnancy and estimate gestational age, develop a plan for continuing care, and counsel the mother about her expectations and concerns. During subsequent visits, you should assess any interim changes in the health status of the mother and fetus, review specific physical examination findings related to the pregnancy, and provide counseling and timely preventive screenings.
Initial Prenatal History
Initial prenatal visits are best timed early in pregnancy, but may occur at later in gestation; tailor your history to where it falls during the mother’s gestational cycle.
Confirmation of Pregnancy
Ask about confirmation of pregnancy: Has the patient had a confirmatory urine pregnancy test, and when? When was her last menstrual period (LMP)? Has she had an ultrasound to establish dates? Explain that serum pregnancy tests are rarely required to confirm pregnancy.
Symptoms of Pregnancy
Has the patient had missed periods, breast tenderness, nausea or vomiting, fatigue, or urinary frequency?
See the table on “Common Concerns During Pregnancy and Their Explanations” for a list of normal as well as concerning symptoms, p. 931.
Concerns and Attitudes Toward Pregnancy
Ask how the patient feels about the pregnancy. Is she excited, concerned, or scared? Was the pregnancy planned and desired? If not, does she plan to complete the pregnancy to term, terminate, or consider adoption? Is a partner, father of the baby, or other family support network involved? As you elicit her viewpoints, use open-ended questions and be flexible and nonjudgmental. Respect diverse family structures, such as extended family support, single motherhood, or pregnancy conceived by sperm donation with or without a partner of either gender. Support the patient’s choices when unexpected admissions arise, such as a pregnancy resulting from a coerced sexual act, or the wish to end the pregnancy.
Current Health and Past Clinical History
Explore any past or present clinical conditions (Fig. 19-10). Pay particular attention to conditions that affect pregnancy, such as abdominal surgeries, hypertension, diabetes, cardiac disorders including childhood surgery for congenital heart disease, asthma, hypercoagulability states from lupus anticoagulant or anticardiolipin antibodies, mental health disorders such as postpartum depression, human immunodeficiency virus (HIV), sexually transmitted infections (STIs), abnormal Pap smears, and exposure to diethylstilbestrol (DES) in utero.
FIGURE 19-10 Explore the health history.
Past Obstetric History
How many prior pregnancies has the patient had? How many were term deliveries, preterm deliveries, spontaneous and terminated pregnancies, and how many were live births? Were there any complications from diabetes, hypertension, preeclampsia, intrauterine growth restriction, or preterm labor? Were there any complications during labor and delivery such as large babies (fetal macrosomia), fetal distress, or emergency interventions? Were deliveries by vaginal delivery, assisted delivery (vacuum or forceps), or cesarean section?
Risk Factors for Maternal and Fetal Health
Does she use tobacco, alcohol, or illicit drugs? What about medications, over-the-counter drugs, or herbal preparations? Does she have any toxic exposures at work, at home, or in other settings? Is her nutritional intake adequate, or is she at risk from obesity? Does she have an adequate social support network and source of income? Are there unusual sources of stress at home or work? Is there any history of physical abuse or domestic violence?
Ask about the genetic and family history of the patient and her partner and/or father. What are the ethnic backgrounds of the patient and father? Is there any family history of genetic diseases such as sickle cell anemia, cystic fibrosis, or muscular dystrophy, among others? Have babies in the family had any congenital problems?
Plans for Breastfeeding
Breastfeeding protects the baby against a variety of infectious and noninfectious conditions, and exerts a protective effect on the mother against breast cancer and other conditions.– Education during pregnancy and clinician encouragement increase the subsequent rate and duration of maternal breastfeeding.
Plans for Postpartum Contraception
Initiate this discussion early, as postpartum contraception reduces the risk of unintended pregnancy and shortened interpregnancy intervals, which are linked to increases in adverse pregnancy outcomes., Plans for contraception will depend on the patient’s preferences, clinical history, and decision about breastfeeding.
Determining Gestational Age and Expected Date of Delivery
Accurate dating is best done early and contributes to appropriate management of the pregnancy. Dating establishes the timeframe for reassuring the patient about normal progress, establishing paternity, timing screening tests, tracking fetal growth, and effectively triaging preterm and postdated labor.
Determining Gestational Age and the Expected Date of Delivery
- Gestational age. To establish gestational age, count the number of weeks and days from the first day of the LMP. Counting this menstrual age from the LMP, although biologically distinct from date of conception, is the standard means of calculating fetal age, yielding an average pregnancy length of 40 weeks. If the actual date of conception is known (as with in vitro fertilization), a conception age which is 2 weeks less than the menstrual age can be used to calculate menstrual age (i.e., a corrected or adjusted LMP dating) to establish dating.
- Expected date of delivery (EDD). The EDD is 40 weeks from the first date of the LMP. Using the Naegele rule, the EDD can be estimated by taking the LMP, adding 7 days, subtracting 3 months, and adding 1 year.
- Tools for calculations. Pregnancy wheels and online calculators are commonly used to calculate the EDD. However, pregnancy wheels vary widely in quality and accuracy, and are often produced as commercial marketing tools. Online calculators may be more reliable, but should be checked for accuracy before routine use.
- Limitations on pregnancy dating. Patient recall of the LMP is highly variable. Even when this date is accurate, the LMP can be affected by hormonal contraceptives, menstrual irregularities, or variations in ovulation that result in atypical cycle lengths. LMP dating should be checked against physical examination markers such as fundal height, and any wide discrepancies should be clarified by ultrasound evaluation. In clinical practice, dating by ultrasound is widespread, regardless of the certainty of the LMP, even though this approach is not currently endorsed by national guidelines.
Concluding the Initial Visit
As you conclude the visit, reaffirm your commitment to the woman’s health and her concerns during pregnancy. Review your findings, discuss any tests or screenings that are needed, and ask if she has further questions. Reinforce the need for regular prenatal care and review the timing of future visits. Record your findings in the prenatal record.
Subsequent Prenatal Visits
Though the optimal number of prenatal appointments has not been well established, obstetric visits traditionally follow a set schedule: monthly until 28 gestational weeks, then biweekly until 36 weeks, then weekly until delivery. Update and document the history at every visit, especially fetal movement felt by the patient, contractions, leakage of fluid, and vaginal bleeding. The physical examination findings at every visit should include vital signs (especially blood pressure and weight), fundal height, verification of fetal heart rate (FHR), and determination of fetal position and activity, as described in Techniques of Examination to follow. At each visit, the urine should be tested for infection and protein.
- Page 1: Intro
- Page 2: Health Promotion and Counseling: Evidence and Recommendations
- Page 3: Thorax and Lungs
- Page 4: References