English abstract
Background: Intrauterine growth restriction is a common complication of pregnancy which is associated with a variety of adverse perinatal complications including fetal morbidity and mortality, and its long-term consequences proceed into adulthood. A recent study has been conducted in SQUH which revealed an incidence rate of 6.86% for IUGR with high perinatal mortality rate among this group of 22 per 1000.
Aim: This study is proposed to find predictive markers that help in early identification and diagnosis of fetuses with growth restriction that may contribute to reduced adverse outcomes. Methods: The study evaluated maternal characteristics (age, pre-pregnancy weight, BMI, weight at 3rd trimester, gravidity and parity), ultrasound measures (amniotic fluid index AFI) and biochemical markers (fasting glucose, insulin, insulin resistance IR, lipid profile and placental growth factor PIGF). The study included a total of 117 pregnant Omani women (control, n=93, IUGR, n=24) with singleton gestation, and non-diabetic in their third trimester. Automated Cobas biochemistry analyzers were used to measure PIGF and insulin, glucose and lipid profile. All maternal details were obtained from a distributed questionnaire, and patient's medical records. Birth weight and baby's gender were recorded after delivery,
Results: Maternal parameters showed a strong positive correlation with the birth weight. Weight at 3rd trimester gave the highest correlation (r = 0.419 p < 0.001) followed by pre-pregnancy weight (r = 0.312 p = 0.001) then age, parity, weight gain, and gravidity respectively. Amniotic fluid index significantly correlated with birth weight as well following pre-pregnancy weight (r = 0.383 p < 0.001). The IUGR group had a significantly lower pre-pregnancy and 3rd trimester weight and parity. They also had lower weight gain and gravidity but results were not significant. As for biochemical parameters, glucose showed a significant negative correlation with birth weight (r = . 0.209 p = 0.024), The IUGR group showed lower values of placental growth factor PIGF, HDL and LDL that were not significant. Triglycerides however, were significantly lower in the IUGR group. In contrary, higher values for insulin and IR were found in the IUGR group. The main predictors of birth weight were: Pre-pregnancy weight 2- weight gain 3- IR 4- parity 5- PIGF. All together explained about 35.9% of the variation in birth weight. Interestingly, plasma PIGF and IR showed opposing trends, which also appeared in their association with birth weight.
Conclusion: Maternal characteristics play a major role in determination of birth weight. IUGR cases in this study were associated with younger maternal age and lower pre pregnancy and gestational weight in combination with low BMI and weight gain. These factors may increase the risk of having low birth weight infants compared to the controls. The relation of PIGF with insulin levels and hence insulin resistance may indicate an in inhibitory role of insulin on PIGF secretion which may explain the difference seen between the control and IUGR. These findings may contribute to the understanding of the role of growth factors in determining birth weight, which could be further investigated in early gestation in future studies.
