Many women older than age 40 have independent medical or fetal indications for antenatal testing. Some experts have suggested antepartum surveillance starting at 37 weeks for women of advanced maternal age; they argue that the risk of stillbirth at this gestational age is similar in frequency to other high-risk conditions for which testing is performed routinely. However, the National Institute of Child Health and Human Development (NICHD) workshop on antepartum fetal monitoring found insufficient evidence that antenatal testing for the sole indication of advanced maternal age reduces stillbirth or improves perinatal outcomes.20
If increased antenatal testing is indicated for a high-risk condition or electively chosen given advanced age, it should include electronic fetal monitoring as well as amniotic fluid volume assessment. Because the risk of fetal loss sharply increased at 40 weeks’ gestation in the study by Reddy and colleagues,6 women older than age 40 should be considered for delivery by 40 weeks’ gestation in the presence of good dating criteria.
Some clinicians also would consider delivery by 39 weeks’ gestation with good dating criteria if the Bishop score is favorable.
Risks of labor and delivery
Multiple variables contribute to a higher cesarean delivery rate
The risk of cesarean delivery increases with advancing maternal age.5,11 This increased risk is a consequence of multiple variables, including the rate of previous cesarean delivery, malpresentation, underlying complications such as preeclampsia and diabetes, and a higher prevalence of dysfunctional labor.21 Further, Vaughn and colleagues noted that the cesarean delivery rate increases in direct proportion to age, with a rate of 54.4% in women older than age 40.5
As Cohen pointed out in a commentary accompanying a study of dysfunctional labor in women of advancing age, “the notion of a premium baby (ie, that the fetus of a woman with a reduced likelihood of having another pregnancy is somehow more deserving of being spared the rigours of labour than the fetus of a young woman) may play a role” in the high rate of cesarean delivery.21,22
Postpartum hemorrhage risk may be lower in older women
Advanced maternal age is assumed to be a risk factor for postpartum hemorrhage.23 The increased risk was thought to be related to the increased incidence of multiple underlying factors, such as cesarean delivery, multiple gestation, and hypertensive disorders of pregnancy.
However, in a retrospective cohort study, Lao and colleagues found that advanced maternal age (≥35 years) served only as a surrogate factor for postpartum hemorrhage due to associated risk factors, obstetric complications, and interventions.24 After multivariate analysis, aging was associated with a decreased rate of postpartum hemorrhage, which declined progressively from ages 25 to 40 years and older, compared with women aged 20 to 24.24
Nevertheless, medical interventions should be readily available at the time of delivery for treatment of uterine atony, especially with multiple gestation and grand multiparity.
Case: Resolved
The patient is admitted to the hospital, where she is given IV magnesium sulfate (6-g load followed by an infusion of 3 g/hr) and betamethasone for fetal lung maturity enhancement. She continues to receive IV fluids as well (125 mL/hr lactated Ringers solution). Uterine activity abates.
IV magnesium sulfate is continued for 36 hours, but urine protein output is not monitored. Her heart rate ranges from 105 to 115 bpm, and blood pressure from 130/80 mm Hg to 138/88 mm Hg. Forty-eight hours after admission, she reports a gradual onset of tightness of the chest and breathlessness. She is agitated, with a pulse of 130 bpm, 30 respirations/min, and room air pulse oximetry of 90%. Rales are noted upon auscultation of both lungs. A radiograph of the chest demonstrates bilateral air-space disease consistent with pulmonary edema. IV furosemide and oxygen (by mask) are provided, with some respiratory improvement.
The patient then reports leakage of amniotic fluid, and preterm rupture of membranes is confirmed on examination. Because steroids for fetal lung maturity have been administered, and given improvement in her pulmonary edema and a footling breech presentation for Twin A, cesarean delivery is performed.
The patient’s immediate postoperative course is uncomplicated. On postoperative day 2, however, she develops recurrent pulmonary edema, as confirmed by physical examination and chest radiograph. She also reports headache, and her blood pressure rises to 164/114 mm Hg—findings consistent with postpartum preeclampsia. Magnesium sulfate and antihypertensive therapy are initiated, along with IV furosemide and oxygen, which improves her respiratory status.
An echocardiogram to rule out peripartum dilated cardiomyopathy finds no evidence of a dilated left ventricle, and the calculated left ventricular ejection fraction (55%) is normal.
After diuresis and improvement in her blood pressure, she is discharged home. By the time of her follow-up office visit 7 days later, her blood pressure has normalized on labetalol therapy.
