Vinutha B.
M.N. Mehta and 
Preeti Shanbag

From the Department of Pediatrics, L.T.M.M. College and L.T.M.G. Hospital, Sion, 
Mumbai 400 022, India.

Reprint requests: Dr. Vinutha B., Department of Pediatrics, University Medical Center, 
Dr. B.R. Ambedkar Circle, Balmatta, Mangalore 575 001, India.

Objective: To assess the Vitamin A status of pregnant women in their third trimester using maternal serum retinol levels as the indicator; and (ii) To assess the impact of postpartum Vitamin A supplementation on the Vitamin A status of exclusively breastfed infants. Design: Prospective randomized single blind controlled study. Setting: Teaching Hospital. Subjects: 109 apparently healthy primi and second gravida women registered at the antenatal clinic were included in the study and followed up for three months postpartum. Serum retinol levels of pregnant mothers in their third trimester (35-37 weeks) and cord blood levels after delivery were estimated. Mothers were then assigned to two groups. The experimental group included 53 mothers who received a single dose of 2 lakh units of Vitamin A orally. The control group had 56 mothers who did not receive Vitamin A. Mothers and infants were followed up for three months. The serum retinol of infants and the breast milk retinol levels were estimated at the end of three months and the results were compared. The growth of the infants was also monitored. Results: Subclinical Vitamin A deficiency was seen in 29.67% of pregnant women. At the end of three months, 69.6% of mothers in the control group had breast milk retinol levels below 30 mg/dl, as opposed to 36.1% in the experimental group. Forty five per cent of infants in the control group had subclinical vitamin A deficiency compared to none in the experimental group. There was no difference in the growth of infants in the two groups. However, the infant serum and the breast milk retinol levels were significantly higher in the supplemented group. Conclusion: There is a high prevalence of inapparent Vitamin A deficiency (29.7%) in pregnant women in their third trimester from lower socio-economic strata. Postpartum Vitamin A supplementation had a beneficial impact on the infant serum retional and the breast milk retinol level but no effect on infant growth.

Key words: Pregnancy, Retinol, Vitamin A deficiency, Vitamin A supplementation.

The role of Vitamin A in critical periods of proliferative growth and tissue develop-ment, as in pregnancy, infancy and childhood is well known. During the period of early fetal development, however, the supply must be closely regulated to ensure that the developing fetus is exposed to neither too much nor to too little Vitamin A because both conditions can have adverse effects. Towards the end of gestation, adequate maternal Vitamin A status and dietary intake are important to maximize the Vitamin A transferred to the fetus in preparation for parturition and lactation(1).

Breast milk is the only source of Vitamin A during the neonatal period for the exclusively breastfed infant. The ability to meet infant requirements depends on the concentration and the volume of breast milk consumed, both of which are influenced by maternal Vitamin A status and dietary intake. Infants breastfed by mothers with adequate Vitamin A levels are protected from Vitamin A deficiency(2).

Recently, changing trends in Vitamin A deficiency in children below 5 years have been noted(3). Instead of older children (2-4 years), infants below 1 year of age have been observed to develop keratomalacia and this is attributed to poor maternal stores(3).

The present study was undertaken to determine whether pregnant women from the lower socio-economic group have adequate Vitamin A stores and are able to protect their breastfed infants from VAD.

This was a planned prospective study carried out over a one-year period from April 1995 to March 1996. The study population comprised 109 apparently healthy primi and second gravida women in their third trimester, registered during early pregnancy at the antenatal clinic of a public teaching hospital. Pregnant women were included in the study after they had completed 34 weeks of gestation. Most of them belonged to the lower socio-economic group with ages ranging from 18 to 35 years. Pregnant women with illness likely to affect Vitamin A metabolism, those with clinical signs of Vitamin A deficiency, women receiving Vitamin A supplementation and those on oral contraceptives 6 months prior to conception, were excluded from the study. Preterm babies, sick babies and infants who were not exclusively breastfed were also excluded.

Women were enrolled into the study after obtaining their informed consent. A detailed history was taken especially with regard to dietary patterns of intake of Vitamin A and Carotene rich food in the diet. The dietary history included the frequency and quantity of intake of selected food items rich in Vitamin A. These food items included dark green leafy vegetables, carrots, sweet potato, pumpkin, mango, papaya, whole milk, egg, liver, fish, meat and dairy products. According to the dietary pattern of intake of vitamin A rich food, women were catagorized as follows: (i) Regular intake: Consumption of at least 50 grams or more of Vitamin A rich food, 2 or more times a week; (ii) Seasonal intake: Intake of 50 grams or more of Vitamin A rich food available only seasonally; and (iii) Low intake: Consumption of less than 50 grams of Vitamin A rich food occasionally less than two times per week.

Detailed clinical examination was performed on each subject.

Serum retinol estimation was done on all pregnant women in their third trimester between 35-37 weeks gestation and on all cord blood samples. Five ml of venous blood was collected, the serum separated and transferred to cold resistant stopped tubes, which were then stored at 4º C taking care not to expose the tubes at any stage to light, as sunlight and artificial light decrease the activity of Vitamin A in the serum. Estimation of serum retinol was done by spectrophotometric method(4-11). After collect-ing the initial samples, the women were randomly assigned to two groups. The experi-mental group consisted of 53 mothers who received a single dose of 2 lakh units of oral Vitamin A (in the form of Aquasol water-miscible Vitamin A containing 50,000 unit per ml), within 48 hours of delivery. Aquasol was the preparation provided by our pharmacy free of cost for our patients. Hence this preparation was used in preference to an oil-based preparation. The control group comprised 56 mothers who did not receive Vitamin A after delivery.

All babies were examined at birth. These mother-infant pairs were followed up for 3 months and monitored for exclusive breast-feeding. Twenty five mother infant pairs did not come for follow up. Among the 84 babies in our follow up, 4 babies in the control group and 3 in the experimental group had upper respiratory tract infection. Two babies in the experimental group had acute gastroenteritis with no dehydration. Stool examination in both these babies was normal. These minor infections were not considered to be significant. At 3 months the serum retinol of the infants and the breast milk retinol levels were estimated by spectrophotometric method. The procedure and conditions for the collection of the breast milk sample was standardized. Breast milk was collected in our newborn follow-up Outpatient Department between 8.30 am and 12.00 noon. Mothers were instructed not to breast feed their babies before coming to the OPD after the early morning feed and milk was pumped from full breast since the concentration of some milk components especially lipids and liposoluble substances such as Vitamin A increases during the suckling period. The milk was pumped with a manual pump from both the breasts by a trained nurse. After mixing, a sample of 5 ml was put into small plastic tubes with screw caps and covered with black paper (to prevent exposure to sunlight) and with ½ - 1 hour placed in a deep freeze at –20º C and then analyzed by spectrophotometric method.

Serum retinol levles between 10-20 mcg/dl were taken as subclinical VAD. Breast milk retinol <30 mcg/dl was taken as boderline deficiency(5).

The data was analyzed using the Student’s ‘t’ test.

One hundred and nine women, 86 primigravida and 23 second gravida were enrolled in the study. Table I shows the dietary Vitamin A intake and the serum retinol levles of 91 women whose sample could be analyzed. Twenty seven of the 91 women (29.7) had subclinical Vitamin A deficiency, all of them with seasonal or low dietary intake. Women with regular intake had no subclinical Vitamin A deficiency.