Fetal growth retardation in relation to maternal smoking and weight gain in pregnancy.

Two types of fetal growth retardation were recognized in term infants. One type was characterized by an abnormally low ponderal index (defined as birth weight in grams X 100 divided by crown-heel length in cubic centimeters.) The other type of growth-retarded infants had abnormally short crown-heel lengths for fetal age. Both types were observed under all conditions studied. However, mothers who smoked cigarettes during pregnancy were more likely to have infants with short body lengths for dates, whereas mothers who had low weight gain in pregnancy were more likely to have infants with low ponderal indices. Social group, prepregnancy weight, parity, marital status, and fetal sex were found to be less determinant of fetal growth than were maternal weight gain and smoking habits.     

Fetal movements and intrauterine growth retardation

Fetal Movement (FM) rate was evaluated in cases of symmetrical and asymmetrical intrauterine growth retardation (IUGR) and was compared to the FM rate in normal pregnancy. In the 25–36th week of gestation there was a significant decrease of FM rate in both groups of IUGR which was more pronounced in the symmetrical group. Also shown, was a gradual trend of increase of the FM rate with advancing gestational age in both groups of IUGR. Cases of asymmetrical IUGR were noted, who had markedly decreased FM until cessation. In this group of IUGR decreased FM demands prompt hospitalization and fetal heart rate monitoring so that possible respiratory failure and impending fetal death can be detected.     

Fetal growth retardation after gastric banding

A 35-year-old woman became pregnant 15 months after gastric banding, during which time she lost 55 kg in weight. During the third trimester, severe vomiting was noted and she lost a further 6 kg. Ultrasound examination showed oligohydramnions and fetal growth retardation of 38%. Enteral nutrition was given until delivery and ultrasound verified normalization of the oligohydramnions and weight gain for the fetus. The woman was delivered by cesarean section of a female infant with birthweight 2,470 g. It is concluded that special care must be taken with regard to the nutritional status of pregnant women who have previously been operated on with gastric procedures for obesity, in order to diminish the risk of fetal growth retardation. Ultrasound examinations should be performed on wide indications and enteral nutrition must start immediately once fetal growth retardation is discovered.     

Fetal growth in multiple pregnancy

A close surveillance of fetal growth in multiple pregnancies is mandatory for the prevention and/or reduction of neonatal morbidity and mortality. Multiples have the same genetically determined growth potential as singletons. However, this growth potential is restricted by the functional capacity of the placenta and uterus. Multiples show a specific growth pattern compared to singletons. Nevertheless, for clinical surveillance, the 10th percentile of singleton growth charts may be used, because significant differences, which may define normally grown multiples as small for gestational age or growth restricted, can only be detected at higher gestational ages, when most of the multiples may have already been delivered. At higher gestational ages, obstetricians should take into account the specific growth pattern for multiples. In multiples with growth discordance, it is necessary to consider or exclude the various causes, and if necessary the clinical follow-up has to be intensified.     

Fetal breathing patterns in intrauterine growth retardation.

Fetal breathing movements were studied with real time ultrasound in 21 normal fetuses and 30 fetuses born small-for-dates (less than the 5th centile). The events of the study period were recorded on punched paper tape which was subjected to computer analysis. In the normal group the percentage time of breathing was 54 +/- 12.7 (mean +/- SD). The breath to breath interval was 1.34 +/- 0.25 seconds and the coefficient of variation of this interval was 49.6 +/- 7.7 per cent. In 17 of the small-for-dates group amount of breathing was reduced with short breathing episodes and long apnoea intervals. In the other 13 patients in the small-for-dates group the coefficient of variation for the breath to breath interval was significantly reduced (39.6 +/- 7.9 per cent, p less than 0.01).     

Fetal growth retardation in the second trimester.

Growth of the fetal head was assessed by serial ultrasonic measurements in a prospective study of a randomly selected group of 126 mothers. Three cases exhibiting second trimester fetal head growth retardation with varying degrees of catch-up growth before term are illustrated.     

Brain growth among fetuses exposed to cocaine in utero: asymmetrical growth retardation

Fetal growth retardation may be associated with maternal cocaine use during pregnancy. The pattern of fetal growth retardation was analyzed in infants born to 80 women who used cocaine, but not alcohol, during pregnancy, and in two comparison groups: 100 infants born to mothers who used neither alcohol nor cocaine during pregnancy and 67 infants whose mothers used alcohol but not cocaine during pregnancy. There were statistically significant differences in head size between the unexposed and cocaine-exposed infants (P less than .001). Notably, head circumference was reduced proportionately more than birth weight in cocaine-exposed infants, a pattern similar to that observed in alcohol-exposed infants. Alcohol- and cocaine-exposed infants were not statistically different in head circumference. We conclude that brain growth of cocaine-exposed infants is similar to that reported for alcohol-exposed infants, and that cocaine-exposed infants may be characterized as having asymmetrical growth retardation.     

Fetal position during pregnancy

In this study of a normal, undelivered population the incidence of each fetal position was reported. Fetal position at 20 weeks' gestation did not correlate with delivery position. Fetal position at 36 weeks was very predictive of fetal position at delivery. Malposition was not associated with premature delivery per se.     

Fetal behaviour in growth retardation: its relationship to fetal blood flow

The fetal behaviour of asymmetrical growth retarded fetuses was compared with that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and echographic examinations for two consecutive hours at 36-38 weeks of gestation. The distribution of gross fetal body movements, fetal breathing movements and fetal eye movements was analysed during the different fetal heart rate patterns. Furthermore, the incidence and organization of fetal behavioural states was investigated. The degree of vascular peripheral resistance was also evaluated by means of pulsed doppler ultrasonic equipment. Growth retarded fetuses were divided into two groups on the basis of the presence or absence of end diastolic flow in the fetal thoracic descending aorta. Growth retarded fetuses showed a delay in the integration of behavioural patterns and a lower coincidence of behavioural states. These findings are particularly evident in the fetuses with a severe increase of peripheral vascular resistance (absence of end diastolic flow in descending aorta). Thus, we suggest that a delay in central nervous system development is present in asymmetrical growth retarded fetuses and that there is a possible relationship of this delay to the degree of peripheral vascular resistance.     

Fetal growth restriction associated with measles virus infection during pregnancy

We report on a 28-week infant with growth restriction starting after 23 weeks' gestation because of measles virus (MV) infection of the mother. Histological findings for the placenta revealed extensive fibrin deposition and necrosis of the villi, and MV antigen was demonstrated in the syncytiotrophoblast by immunostaining. The MV-specific IgM level in the infant was negative, but that of the mother was positive. Therefore, we speculate that growth restriction is not attributed to direct infection with MV, but to placental dysfunction due to a decrease in intravillous blood flow and oxygen supply to the fetus.     

Fetal renal failure associated with intrauterine growth retardation

Four preterm infants with severe intrauterine growth retardation had renal failure from birth. The amount of asphyxia associated with the birth process did not fully explain the renal failure. Before delivery all for fetuses had severe oligohydramnios and an empty urinary bladder. These observations strengthen the view that severe intrauterine growth retardation may be accompanied by oligohydramnios caused by fetal renal failure.     

Fetal lung growth in experimental utero-abdominal pregnancy

We removed rat fetuses from the uterus without disturbing the placental implantation site, placing the fetuses in the peritoneal cavity either within intact membranes (with or without amniotic fluid) or outside of the fetal membranes. Untouched littermate fetuses served as controls. The surgery was performed on day 17 of gestation and the outcome was analyzed at term, 4 days later. The utero-abdominal pregnancies with intact membranes and amniotic fluid yielded fetuses in all respects indistinguishable from littermate controls. Extrauterine fetuses maintained within their membranes but without amniotic fluid as well as extrauterine and extramembranous fetuses displayed identical features: body weight was slightly reduced; after correction for body weight, only their lungs weighed significantly less and contained less deoxyribonucleic acid. In addition, fetuses in these two groups had multiple joint contractures and occasional webbing of the skin. These experimental findings in rats indicate an important role of amniotic fluid in fetal development, especially of the lung.     

Fetal blood flow in pregnancies complicated by intrauterine growth retardation

A noninvasive pulsed Doppler ultrasound technique was used to characterize blood flow in the descending thoracic aorta and the intra-abdominal part of the umbilical vein in 159 fetuses suspected of intrauterine growth retardation (IUGR) on the basis of ultrasound fetometry. From this group, 74 infants with IUGR (defined as gestational age-related birth weight of 2 standard deviations [SD] or more below the population mean) were born. The blood flow results were not available to the clinicians managing the pregnancies. Blood flow mean velocity in the fetal aorta was lower, pulsatility index and rising slope higher, and umbilical volume flow and umbilical flow per 100 g placental tissue were lower in the pregnancies with IUGR than in 21 normal pregnancies. The waveform of the maximum aortic velocity envelope was related to operative delivery for fetal distress, Apgar score, and umbilical cord blood pH. The pulsatility index and the configurational assessment of the diastolic part of the waveform were combined to form a new concept, the blood flow class. The blood flow class was abnormal in 57% of the fetuses classified as having IUGR at birth and in 93% of those growth-retarded fetuses who subsequently developed signs of fetal distress requiring operative delivery. Waveform analysis, in terms of blood flow class, seems to be a useful tool in the surveillance of fetuses when IUGR is suspected. Abnormal blood flow class is a marker of fetal distress and probably gives an earlier indication than antenatal nonstressed cardiotocography. The results of this study point to a strong association between IUGR and impaired fetal blood flow. The aortic volume blood flow, unlike waveform analysis, does not seem to be a variable sensitive enough to predict fetal outcome in the individual pregnancy.     

Smoking during pregnancy: risk for intrauterine growth retardation and persisting microsomia

Smoking during pregnancy is a major risk factor for intrauterine growth retardation. The aim of the Thuringian SGA - (small-for-gestational-age) - study was to evaluate the effects of maternal smoking during pregnancy on birth weight and length as well as postnatal growth dynamics and catch-up growth.Between 1992 and 2002 in all 2 447 liveborn children were assessed with birth weight (GG) <10th percentile and/or birth length (GL) <- 2.0 SDS. A questionnaire was sent to 383 parents of severe SGA children (GG and/or GL <- 2.5 SDS) to report weight and height of the children actually. 108 reports could analysed (mean age 8.0±3.4 years of life).The number of SGA babies in regard to all liveborn children decreased from 14.1% to 9.4% between 1992 and 2002. 14% of SGA babies were born preterm. The mean nicotine abuse was 2 cigarettes per day (range 0-40). 17.6% of the mothers of SGA babies were smoking, whereas in severe SGA 26.9% of smokers was recorded. There is a inverse correlation of nicotine abuse with birth weight (r=- 0.09; p<0.01) or birth length (r=- 0.08; p<0.01). Catch-up growth did not exist in 30.6% of the severe growth restricted children. The risk for short stature in later life was doubled in SGA children.Nicotine abuse during pregnancy is a risk factor for an SGA baby and could have long-lasting effects on growth dynamics during childhood with a lack of catch-up growth.     

Fetal growth potential and pregnancy outcome

Although the association of fetal growth restriction and adverse pregnancy outcomes is well known, lack of sensitivity limits its clinical value. To a large extent, this limitation is a result of traditionally used method to define growth restriction by comparing fetal or birth weight to population norms. The use of population norms, by virtue of their inability to fully consider individual variation, results in high false positive and negative rates. An alternative, calculating fetal individually optimal growth potential, based on physiological determinants of individual growth, is superior in predicting adverse outcomes of pregnancy. Impairment of fetal growth potential identifes some adverse pregnancy outcomes that are not associated with growth restrction defined by population norms. When compared with traditional population-based norms, fetal growth potential is a better predictor of several important adverse outcomes of pregnancy which include: stillbirth, neonatal mortality and morbidity, and long-term adverse neonatal outcomes like neonatal encephalopathy, cerebral palsy and cognitive abilities. Impairment of individual growth potential is also strongly associated with spontaneous preterm delivery. Although definitive interventional trials have not been conducted as yet to validate the clinical value of fetal growth potential, many observational studies, conducted in various populations, indicate its significant promise in this respect.