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FOETO-PLACENTAL WEIGHT RELATIONSHIP IN NORMAL PREGNANCY AND PRE-ECLAMPSIA-ECLAMPSIA - A COMPARATIVE STUDY

Pandit A Palaskar*, Kamlesh R Chaudhary**,Niranjan M Mayadeo***
*Registrar; **Lecturer; ***Asso. Prof., Department of Obst. and Gynaec, KEM Hospital, Parel, Mumbai 12.

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The placenta being a foetal organ is small when the foetus is small, but weight is a poor indicator of placental adequacy. However, low placental weight does decrease functional reserve of the placenta.

A comparative study of foeto-placental weight relationship was carried out at our Institute. 100 cases were studied from pre-eclampsia-eclampsia which were compared with 100 normal pregnancies as control group. In normal pregnancies, the mean birth weight was 2790 gms, the mean placental weight was 475 gms., the mean foeto-placental ratio was 5.87:1 and the mean placental coefficient was 0.171. In pre-eclampsia-eclampsia the mean birth weight was reduced to 2368 gms and the mean placental weight reduced to 392 gms. The mean foeto-placental ratio was increased to 6.04 : 1 and the mean placental co-efficient decreased to 0.165.

INTRODUCTION

The placenta - ‘the life of the foetus in utero’ - functions diversely to support the growth of the foetus, interacts with the two individuals, the mother and the developing foetus. It is the most accurate record of the infants prenatal experiences (Benirschke, 1981).

During pregnancy, the placental mass maintains a dynamic relationship with the weight of developing foetus. Being a disorder of the chorionic villi, pre-eclampsia - eclampsia leads to various changes in the placenta with the consequent affection of the foetus.

In the present study, an attempt is made to study the foeto-placental weight relationship in pre-eclampsia - eclampsia, which is compared with normal pregnancies.

MATERIAL AND METHODS

This prospective study of 200 cases was carried out in our Institute. 100 cases were from pre-eclampsia - eclampsia group and 100 cases were normal pregnancies as control group.

Patients with clinical diagnosis of pre-eclampsia - eclampsia were included in the study. Patients with gestational age less than 32 weeks were excluded from study. As soon as cases from above groups were admitted in labour room, detailed obstetric and medical history was recorded and clinical examination done. Necessary investigations carried out. After delivery babies weighed. The placentae examined after delivery. Adherent clots removed, placentae washed thoroughly with water, cord cut 4 cm from insertion and placentae weighed. The foeto-placental weight relationship calculated by following formulae.

Statistical significance was analyzed with chi - square test and standard error of proportion between two means.

OBSERVATIONS AND RESULTS

TABLE 1 Distribution of birth weight
Birth weight	Control group (n=100)	Pre-eclampsia - eclampsia(gms) (n=100)
1001-1500	0	10
1501-2000	0	15
2001-2500	20	24
2501-3000	64	42
3001-3500	16	09
Total	100	100

As compared to control group, low birth weight babies were common in pre- eclampsia - eclampsia (50%).

TABLE 2 Distribution of placental weight
Placental weight	Control group(n=100)	Pre-eclampsia-eclampsia(gms) (n=100)
251-350	0	25
351-450	44	52
451-550	56	23
551-650	—	—
Total	100	100

In control group, 56% of placentae weighted 451 to 550 gms, whereas in pre-eclampsia - eclampsia 77% of placentae were less than 450 gms.

The mean placental weight in control group was 475 gms and in pre-eclampsia - eclampsia 392 gms.

DISCUSSION

The foeto-placental unit is adversely affected in pre-eclampsia-eclampsia. Due to placental insufficiency foetal growth is affected. According to Little and Thomson et al, for evaluation of foetus, weight of placenta is not enough but the foeto-placental ratio is important.[1,5]

TABLE 3 Foeto-placental ratio and placental co-efficient
Group	Mean birth wt (gm)	Mean Placental wt (gm)	F-P Ratio	Placental co-efficient
Control Group	2790	475	5.87	0.171
Pre-eclampsia –eclampsia	2368	392	6.04	0.165

Fox states that the placenta being a foetal organ is small when the foetus is small and low placental weight does decrease functional reserve of the placenta.[4]

TABLE 4 Comparison with different series
Series	Year	Group	FP Ratio	Placental Co-efficient
		A	5.53	0.182
Saigalet al	1970	B	6.06	0.165
		A	6.56	0.152
Daset al	1996	B	5.60	0.178
		A	5.87	0.171
Present study	2001	B	6.04	0.165

A - Control group, B - pre-eclampsia-eclampsia

Thomson et al observed that, in severe preeclampsia-eclampsia, placental weight and birth weight were both below average, but their ratio was slightly increased.[5] Saigal et al observed F-P ratio 6.06 : 1 and placental coefficient 0.165 in pre-eclampsia-eclampsia.[2] However, Das et al in their analysis of placentae from pre-eclampsia - eclampsia found that the placentae were lighter in weight, lesser in diameter and foeto-placental ratio was diminished.[3]
In present study, the foeto-placental ratio in pre-eclampsia-eclampsia increased to 6.04 : 1 and the placental co-efficient decreased to 0.165, suggesting decreased placental weight in pre-eclampsia - eclampsia, as compared to normal pregnancies.

CONCLUSION

Both the foetal and placental weight is decreased in pre-eclampsia-eclampsia, but the foeto-placental ratio is increased and the placental co-efficient is decreased as a result to placental affection.

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REFERENCES :

1.Little William A. Am Jr Obst and Gynecol 1960; 79 : 134-37.

2.Saigal Saroj and Shrivastav JR. Indian Pediatrics 1970; 7 (2) : 68-77.

3.Das B, Dutta D, Chakraborty S, Math P. Jr Obst and Gynecol 1996; 46 (1) : 40-46.

4.Fox HC. Pathology of Placenta : WB Saunders Co. 1978; 58-66.

5.Thomson AM, Billewicz WZ, Hytten FE. Jr Obst and Gynecol Br Commonwealth 1969; 76 (10) : 865-72.

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