What Bothers Mother
Infections and other medical conditions during pregnancy raise the probability of a baby being born with weight problems, if not serious health challenges
By Miles Dumalagan
Already difficult by nature, pregnancy can be further complicated and made more difficult by certain conditions that the mother might be suffering from. Some of these illnesses are serious enough to threaten the life of both mother and fetus.
Infections and other medical conditions increase the likelihood of fetal infection and poor neonatal outcome. In many cases, they account for intrauterine growth restriction, which is associated with low weight at birth.
For these reasons, says perinatologist Carmen Adela Juson-Perez of the Philippine Children's Medical Center, fetal growth monitoring is a vital aspect of pregnancy management to avoid the dangers that growth restriction poses to the life and well-being of the fetus.
Fetal Compromise
The term fetal growth restriction applies to all fetuses whose birth weight is below the 10th percentile of a population at a given gestational age. Growth potential varies by race and from one individual to another.
This is one reason for significant differences in birth weight among infants of the same gestational age.
"The causes of fetal compromise in intrauterine growth restriction (IUGR) range from inadequate uteroplacental perfusion to compression of the umbilical cord due to oligohydramnios," says Perez, noting that insufficient placental microcirculation or deterioration in maternal oxygenation causes IUGR.
Perez notes that IUGR can be detected early using serial fetal ultrasound mesurements. This allows closer intrauterine fetal surveillance, which includes nonstress test, fetal movement counting, biophysical profile, and Doppler flow studies.
For Perez "successsful management of IUGR rests in the correct antenatal diagnosis of fetal growth restriction, stabilization of maternal condition, and knowledge of the right time of delivery."
It goes without saying that good prenatal care must include identification, monitoring, and proper management of infections and other conditions especially for women at high risk.
Maternal Infections
Almost any maternal infection with severe systemic manifestations may result in premature labor, miscarriage, or stillbirth. Regardless of the severity of the maternal infection, agents frequently infect the fetus-with serious sequelae, including being born small for gestational age.
Toxoplasmosis-a protozoal infection caused by Toxoplasma gondii-during pregnancy may cause abortion or infection of the fetus through the placenta. The earlier the infection is acquired, the more virulent the fetal infection would be. Affected infants usually have evidence of generalized disease with low birth weight, anemia, jaundice, and hepatosplenomegaly. They manifest with neurological disease with convulsions, mental retardation, and intracranial calcifications. Some infected infants have microcephaly or hydrocephaly.
Rubella or German measles is known to have been directly responsible for inestimable pregnancy wastage and severe congenital malformations. It is one of the most teratogenic agents known. Fetal infections are less likely to cause congenital malformations as the duration of pregnancy increases. Clinical manifestations correlate best with timing of maternal infection and organogenesis. Infants born with congenital rubella syndrome (CRS) may have fetal growth restriction, eye lesions (cataracts, glaucoma, and microphthalmia), heart disease (septal defects, patent ductus arteriosus, and pulmonary artery stenosis), chronic diffuse interstitial pneumonitis, osseus changes, sensorineural deafness, CNS defects, and chromosomal abnormalities.
It is important to remember that infants born with CRS may shed the virus for months and pose as a threat to other infants and vulnerable adults who come in contact with them. Extended rubella syndrome (with progressive panencephalitis and type 1 diabetes) may be manifested in as many as one-third of asymptomatic infants at birth. This may not develop clinically until the second or third decade of life.
Cytomegalovirus (CMV) is a ubiquitous DNA herpes virus that is a common cause of perinatal infection. Congenital CMV infection, termed cytomegalic inclusion disease, causes a syndrome that includes LBW, microcephaly, mental and motor retardation, sensorineural deficits, jaundice, hemolytic anemia, and thrombocytopenic purpura.
The virus may be transmitted vertically from the mother to fetus. Most infections during pregnancy are recurrent and are less often associated with clinically apparent sequelae than primary infection.
Of the two types of herpes simplex virus, HSV 2 is recovered almost exclusively from the genital tract and transmitted in the great majority of instances by sexual contact. Infection is rarely transmitted across the placenta or intact membranes. Rather, virus shed from the cervix or the lower genital tract infects the fetus. The virus may also invade the uterus following membrane rupture or come into contact with the fetus at delivery.
First-episode infection in early pregnancy is probably not associated with an increased risk of spontaneous abortion. Late-pregnancy primary infection results in an increased risk of preterm labor. Disseminated neonatal infection is associated with at least 60-percent mortality rate. Serious ophthalmic and CNS damage has been identified in at least half of the survivors.
Syphilis has in the past accounted for nearly a third of stillbirths. The continued prevalence of syphilis at delivery is associated with HIV infection, lack of prenatal care, substance abuse, reinfection, and treatment failures. While no longer as widespread, infection with syphilis at any stage of pregnancy may induce preterm labor, fetal death, and neonatal infection (transplacental or perinatal).
Complicating Medical Conditions
Apart from infections, other disorders may compromise the health of the fetus.
Anemia, for instance, is associated with preterm delivery, fetal growth restriction, perinatal mortality, and LBW infants.
Chronic vascular disease especially when further complicated by superimposed preeclampsia commonly causes growth restriction. Pregnancy-induced hypertension with underlying vascular or renal disease would likely cause fetal growth restriction, chronic renal disease, and chronic hypoxia.
Chronic renal insufficiency can cause common complications like chronic hypertension, anemia, preeclampsia, preterm delivery, and fetal growth restriction.
Maternal diabetes may result in a high incidence of intrauterine deaths after the 36th week of gestation in unmonitored and poorly controlled mothers. Some studies show that spontaneous abortion is linked with poor glycemic control. The incidence of severe malformations is a consequence of poorly controlled diabetes (before conception and in early pregnancy). Overt diabetes antedating pregnancy is also a risk for preterm birth.
Perez points out that treatment of underlying maternal disease can improve the fetal condition and prevent untimely delivery. "For pregnant women who have cardiovascular disease, particularly those with functional class 3 and 4, bed rest talaga sila," she stresses.
Multifetal pregnancy is also likely to restrict growth of one or more fetuses in about 21 percent of cases. Abnormal placentation, decrease in placental size, and abnormal placental vascular anasomosis are the primary factors that impair growth in multifetal pregnancies.
Alcohol and Prohibited Drugs
The bad effects of alcohol on the fetus have been medically recognized as early as the 1800s and put together in what is now known as fetal alcohol syndrome (FAS).
As such, the Philippine Obstetrical and Gynecological Society (POGS) warns in its Maternal Nutrition Guidelines that alcohol is an absolute no-no for pregnant women because alcohol crosses the placenta and "there is no known safe level of intake during pregnancy." Neither have the effects of episodic drinking been clearly defined.
A bottle of beer, a glass of wine or mixed drink contains about half an ounce of absolute alcohol, and even moderate alcohol intake of four to six drinks, or two to three ounces of alcohol, could be harmful.
Studies show that FAS has been documented in ten percent of infants of mothers who have had two or three drinks per day, and up to 30-percent incidence in those whose mothers are heavy drinkers (five or more drinks a day).
"High alcohol levels build up in the fetus and produce direct toxic effects that are most severe in the early phases of pregnancy during blastogenesis and differentiation," says the POGS.
While FAS is the result of chronic alcohol abuse during pregnancy, fetal outcomes vary in severity. The POGS notes that the consequences range from no apparent fetal sequelae to IUGR to severely damaged infants. "Associated features include prenatal and postnatal growth failure, developmental delay, microcephaly, epicanthal fold, and facial and sekeletal joint abnormalities. These mothers also experience a higher rate of spontaneous abortion, abruptio placenta, and low-birth-weight delivery," the society warns.
Use of illegal and highly regulated drugs during pregnancy like heroin, marijuana, amphetamines, opium derivatives, and barbiturates particularly in large doses, is also harmful to the fetus. Intrauterine distress, LBW, and serious compromise as the consequence of drug withdrawal soon after birth are well documented. Mothers who use illegal drugs often do not seek prenatal care, and even if they do, don't admit to using them.
Other Physical Demands
For women medically at high-risk, strenuous physical activities like doing household chores (washing or ironing clothes, lifting heavy objects) or physical labor could also adversely affect pregnancy outcome. Sometimes, the energy loss cannot be simply compensated by adequate caloric intake. Uterine blood supply may be diminished by upright posture while working, affecting the supply of oxygen and nutrients to the fetus. Moreover, mental stress may be worsened by bad working environment with exposure to smoke.
Working Together
If prenatal care is a must for pregnant women regardless of their state of health, all the more that it should be indispensable for those suffering from these foregoing health conditions.
And once these conditions have been identified and the risks to the fetus established, the obstetrician and pediatrician must effectively work hand in hand to anticipate perinatal problems and take prompt preventive and therapeutic measures.
Perez says the general measures for the care of mothers at risk include monitoring her well-being through clinical observation and limiting the extent of some of the physiologic changes in pregnancy with enough bed rest and by lying more often on left lateral position to avoid compression of the vena cava.
Sadly, getting good prenatal care for many Filipino women has been hampered by lack of knowledge on the importance of prenatal care, low socioeconomic status, and lack of access to health-care services.
Still, Perez advises pregnant women "to have monthly prenatal check-up from the first to the sixth month, twice-monthly from the 28th to the 32nd week, and weekly from 33rd to the time of delivery."
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