A 29-year-old woman, gravida 1 para 0, at 12 weeks gestation comes to the office for prenatal care. The patient was hospitalized at 7 weeks gestation for hyperemesis gravidarum. Since the hospitalization, she has received intravenous hydration several times in the emergency department due to dehydration from persistent nausea and vomiting. Despite taking antiemetics frequently, the patient is unable to eat or drink much. She is able to tolerate prenatal vitamins, which she takes with metoclopramide. Blood pressure is 90/50 mm Hg. Prepregnancy BMI was 18 kg/m2. Weight is 50 kg (110.2 lb), a decrease of 2 kg (4.4 lb) from her prepregnancy weight. Fetal heart tones are normal by Doppler. The patient is concerned about her weight loss and whether it will affect the baby. This patient is at greatest risk for which of the following pregnancy complications?
Complications of inappropriate pregnancy weight gain | |
Excessive weight gain |
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Inadequate weight gain |
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Recommendations for weight gain in pregnancy depend on prepregnancy BMI, which is an indicator of baseline maternal fat and nutrient stores. A patient with an underweight prepregnancy BMI (ie, <18.5 kg/m2), such as this patient, has low baseline nutrient stores and therefore requires greater gestational weight gain (a total of 12.7-18 kg [28-40 lb]) to maintain a healthy pregnancy.
This patient is underweight and has hyperemesis gravidarum, which is characterized by severe, persistent nausea and vomiting that can extend past the first trimester. Although the pathophysiology of hyperemesis itself does not affect the fetus, mothers with hyperemesis gravidarum frequently have inadequate gestational weight gain. Low prepregnancy BMI and poor nutrient intake during pregnancy increase the risk of fetal growth restriction, low birth weight, and preterm delivery.
(Choice A) Risk factors for cervical insufficiency, a cause of painless second-trimester pregnancy loss, include inherited collagen defects (eg, Ehlers-Danlos syndrome) and prior cervical surgery (eg, cervical conization) because these conditions cause structural weakness of the cervix. Although patients with inadequate gestational weight gain are at increased risk for preterm delivery due to depletion of maternal nutrient stores, they are not at risk for cervical weakness.
(Choice B) Unlike adult anemia, which is commonly due to iron deficiency (eg, inadequate nutrition), fetal anemia typically occurs due to fetal red blood cell destruction (ie, hemolysis). Risk factors include Rh alloimmunization and in utero infection (eg, Parvovirus B19) but not poor weight gain in pregnancy.
(Choice D) The chief risk factor for neural tube defect is inadequate folate consumption. This patient is able to take her prenatal vitamins, which contain folate, making neural tube defect an unlikely complication.
(Choice E) Placenta previa occurs due to abnormal placentation such that the placenta overlies the cervical os. The most common risk factor is prior cesarean delivery. Hyperemesis gravidarum and inadequate gestational weight gain do not affect placental location.
Educational objective:
Hyperemesis gravidarum is severe, persistent nausea and vomiting in pregnancy that can lead to inadequate gestational weight gain. Underweight pregnant patients (ie, BMI <18.5 kg/m2) and those with inadequate gestational weight gain are at increased risk for fetal growth restriction and preterm delivery.