“We have found that even women considered at low risk for stillbirth face an enormously increased risk of recurrence,” he said. “Every stillbirth must be taken seriously, and subsequent pregnancies should be carefully monitored.”
“Stillbirth is not just one phenomenon,” said Salihu, an obstetrician-gynecologist and researcher at the University of South Florida in Tampa. “The causes are likely to be different when the loss occurs antepartum — during pregnancy and before labor begins — than when it occurs intrapartum, or during labor.”
The latter can occur, for example, if the baby is strangled by the umbilical cord during the birth process.
The single largest condition associated with stillbirth is fetal growth restriction, found in 43 percent of cases and in the majority of cases previously considered unexplained, Reddy said. “In up to 75 percent of pregnancies,” she wrote, “fetal growth restriction may be missed and is incorrectly diagnosed about 50 percent of the time.”
VALUE OF SONOGRAMS
Impaired fetal growth can result from a problem with the placenta, causing deficient blood flow and nutrients to the developing fetus. If detected in time — for example, through sonograms every four to six weeks starting at 28 weeks of gestation, and every two to four weeks if the problem is detected — a growth-restricted fetus could be delivered early and stillbirth prevented, Reddy explained in an interview. In one in five cases of fetal growth restriction, she said, the problem is likely to recur in subsequent pregnancies.
To distinguish between a small healthy baby and one that is growth-restricted, parental size, date of the woman’s last menstrual period and a dating sonogram done in the first trimester must be taken into account.
Other conditions that can impair growth in the womb are birth defects, chromosomal abnormalities, genetic syndromes and viral infections, she said.
In her review of the factors that predict recurrent stillbirth, Reddy listed two that women have an opportunity to control: obesity and smoking. Women who quit smoking after a stillbirth greatly reduce their risk of experiencing another. Older women; blacks; women with an underlying disease like diabetes, hypertension, clotting or metabolic disorders; women who had a prior Caesarean delivery; and those who remain pregnant well past their due date also face a higher-than-average risk of stillbirth.
If a genetic or chromosomal abnormality was the cause of a stillbirth, the risk of recurrence can vary from 1 percent if the baby had an extra chromosome to as high as 50 percent for genetic disorders like familial DiGeorge syndrome. In subsequent pregnancies, the woman could undergo prenatal testing to determine whether the fetus was free of the problem.
For a woman with diabetes, achieving a normal blood glucose level before conceiving, and maintaining it throughout the pregnancy, can reduce the risk of congenital abnormalities and stillbirth, Reddy noted. It is also important for hypertensive women to keep their blood pressure well controlled.
Women at risk of stillbirth are advised to count fetal kicks, say, for half an hour twice a day, starting at 28 weeks gestation. If a significant drop in fetal activity is noted, Salihu said, they should seek immediate medical care.
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