Indmedica Home | About Indmedica | Medical Jobs | Advertise On Indmedica
Search Indmedica Web
Indmedica - India's premier medical portal

Journal of the Anatomical Society of India

Morphological Study of Placenta in Pregnancy Induced Hypertension With its Clinical Relevance

Author(s): Udainia, A; Jain, M.L.

Vol. 50, No. 1 (2001-01 - 2001-06)

Department of Anatomy, Government Medical College, Surat. Gujarat. INDIA

For Reprints, request the first author.

Abstract.

Morphological study of placenta in pregnancy induced hypertension with its clinical relevance has been conducted inGovernment Medical College and New Civil Hospital, Surat. The study has been carried out on seventy five cases of pregnancy inducedhypertension and twenty five cases of normotensive pregnancy. Weight of newborn baby and placental weight were studied.

The mean weight of newborn baby is 2640 grams in control group, 2480 grams in mild hypertension and 2050 grams in severe hypertension. This indicates that weight of newborn baby is significantly low in pregnancy induced hypertension and it decreases with increase in severity of hypertension. Weight of newborn baby shows more variability in pregnancy induced hypertension (Coefficient of Variation 27.47) as compared to the control group (Coefficient of Variation 19.70)

The mean placental weight is 495 grams in control group, 435.63 grams in mild hypertension and 371.43 grams in severe hypertension. Thus there is a significant lowering of placental weight in pregnancy induced hypertension. Placentae weighing less than 250 grams are found only in pregnancy induced hypertension. As severity of hypertension increases, placental weight decreases as confirmed by minimum placental weight of 250 grams in mild hypertension and 200 grams in severe hypertension. A significant increase in the incidence of intrauterine growth retardation and still birth is found with lower placental weight. Low birth weight is associated with low placental weight.

Between placental weight and foetal weight, if the value of one is known, we can calculate the approximate value of the other with the help of equations derived from the data in control, mild pregnancy induced hypertension and severe pregnancy induced hypertension groups respectively.

Key words : Placental Weight, Weight of Newborn Baby, Pregnancy Induced Hypertension.

Introduction:

Reproduction is a feature exhibited by both unicellular and multicellular organisms and essential for the perpetuation of the species. In human, sexual reproduction takes place. Mother and foetus are the two important ends of reproduction. The intrauterine existence of foetus is dependent on one vital organ- “The Placenta”. Placenta is a vital organ for maintaining pregnancy and promoting normal foetal development. It is some times described as the mirror of the perinatal period, but a mirror, which is not yet sufficiently polished. Still one of the common methods of investigation of the factors endangering the foetus and new born during the perinatal period is the examination of placenta.

Hypertensive disorders complicating pregnancy are common and form one of the deadly triad along with haemorrhage and infection, that results in large number of maternal deaths and there off foetal deaths. Since all anabolites needed for foetal metabolism come from the mother's blood and foetal catabolites are passed back into the atmother's circulation through the placenta; the examination of placenta gives a clear idea of what had happened with it, when it was in the mother's womb and what is going to happen with the foetus in the future. With this objective the present study was carried out.

Material and Methods :

The study of gross morphology of placenta with its clinical significance was conducted in the Department of Anatomy, Government Medical College, Surat. The placentae were collected from labour room and gynaecology operation theatre, New Civil Hospital, Surat. A total of 100 cases were studied.

Out of 100 cases, 75 cases belonged to parturients having pregnancy induced hypertension 25 cases belonged to normal pregnancy (Control Group). In pregnancy induced hypertension, only those cases having blood pressure ranging 140/90mm of Hg and above, with or without oedema, and/or proteinuria were included. Some cases also had eclamptic fits. None of these cases had hypertension prior to pregnancy. In normal pregnancy group, only those cases with normal blood pressure without oedema or proteinuria were included.

The mothers and their neonates identified for this study were given code numbers and studied the hospital. Placentae with cord and membranes were collected immediately after delivery. Any abnormality of cord and membranes was noted. The placentae along with the umbilical cord identified by corresponding code numbers were preserved in 10% formalin solution (in water).

All the cases of Pregnancy Induced Hypertension were divided into mild and severe categories depending upon the frequency and intensity of the abnormalities listed in Table I.

TABLE I: INDICATORS OF SEVERITY OF PREGNANCY INDUCED HYPERTENSION

S. No. Indicators Mild
Pregnancy
Induced
Hypertension
Severe
Pregnancy
Induced
Hypertension
1. Diastolic blood pressure <100 mm Hg 110 mm Hg or higher
2. Proteinuria Trace to 1 + Persistent 2+ or more
3. Convulsions Absent Present t(eclampsia)
4. Visual disturbances Absent Present
5. Foetal growth restriction Absent Obvious
6. Headache Absent Present
7. Upper abdominal pain Absent Present
8. Oliguria Absent Present
9. Serum Creatinine Normal Elevated
10. Hyper bilirubinemia Absent Present
11. Thrombocyto penia Absent Present
12. Liver enzyme delevation Minimal Marked
13. Pulmonary Oedema Absent Present

Observations and Results :

The observations of weight of newborn babies were recorded under eight groups as shown in Table II and III.

TABLE II: WEIGHT OF NEWBORN BABY

Group No. Weight(Grams) Control Pregnancy
Induced
Hypertension
(PIH)
No of
Cases
Percentage No of
Cases
Percentage
1. 501–1000 4 5.34
2. 1001-1500 1 4.00 6 8.00
3. 1501-2000 2 8.00 15 20.00
4. 2001-2500 5 20.00 25 33.33
5. 2501-3000 14 56.00 20 26.67
6. 3001-3500 1 4.00 3 4.00
7. 3501-4000 2 8.00 1 1.33
8. 4001-4500   1 1.33
  Control PIH
Mean Weight of Newborn baby 2640 2280
Maximum Weight of Newborn baby 3600 4250
Minimum Weight of Newborn baby 1500 1000
Coefficient of variation 19.07 27.47
Standard Deviation 503.45 626.32

TABLE III: WEIGHT OF NEWBORN BABY IN PIH CASES

Group
No
Weight
(Grams)
Mild
Pregnancy
Induced
Hypertension
Severe
Pregnancy
Induced
Hypertension
No of
Cases
Percentage No. of
Cases
Percentage
1 501-1000 2 5.00 2 5.71
2 1001-1500 1 2.50 5 14.29
3 1501-2000 4 10.00 11 31.43
4 2001-2500 15 37.50 10 28.57
5 2501-3000 14 35.00 6 17.14
6 3001-3500 2 5.00 1 2.86
7 3501-4000 1 2.50 - -
8 4001-4500 1 2.50 - -
  Mild Severe
Mean Weight of Newborn baby 2480 2050
Maximum Weight of Newborn baby 4250 3250
Minimum Weight of Newborn baby 1000 1000
coefficient of variation 24.03 28.56
Standard Deviation 595.94 585.48

The mean weight of newborn baby was 2640 grams in control group, 2480 grams in mild hypertension and 2050 grams in severe hypertension. This indicates that weight of newborn baby is significantly low in pregnancy induced hypertension and it decreases with increase in severity of hypertension. Weight of newborn baby shows more variability in pregnancy induced hypertension (Coefficient of variation 27.47) as compared to the control group (Coefficient of Variation 19.07).

The relation between severity of pregnancy induced hypertension and mean weight of newborn baby is shown in Figure 1. From the figure it is observed that weight of newborn baby decreases with increase in severity of hypertension.

The observations of weight of the placentae are recorded under eleven groups as shown in Tables IV and V.

TABLE IV: WEIGHT OF PLACENTA

Group
No
Weight
(Grams)
Control Pregnancy
Induced
Hypertension
(PIH)
No of
Cases
Percentage No. of
Cases
Percentage
1. 151-200 1 1.33
2. 201-250 1 4.00 6 8.00
3. 251-300 2 8.00 9 12.00
4. 301-350 1 4.00 10 13.33
5. 351-400 1 4.00 21 28.00
6. 401-450 5 20.00 11 14.67
7. 451-500 4 16.00 7 9.33
8. 501-550 6 24.00 3 4.00
9. 551-600 1 4.00 5 6.67
10. 601-650 3 12.00 2 2.67
11. 651-700 1 4.00
  Control PIH
Mean Weight of placenta 495.00 405.67
Maximum Weight of Placenta 700.00 650.00
Minimum Weight of Placenta 250.00 200.00
Coefficient of variation 23.05 25.05
Standard Deviation 114.11 101.64

TABLE V: PLACENTAL WEIGHT IN PIH CASES

Group
No
Weight
(Grams)
Mild
Pregnancy
Induced
Hypertension
Severe
Pregnancy
Induced
Hypertension
No of
Cases
Percentage No. of
Cases
Percentage
1 151-200 1 2.86
2 201-250 3 7.50 3 8.57
3 251-300 3 7.50 6 17.14
4 301-350 3 7.50 7 20.00
5 351-400 11 27.50 10 28.57
6 401-450 6 15.00 5 14.29
7 451-500 7 17.50
8 501-550 2 5.00 1 2.86
9 551-600 3 7.50 2 5.71
10 601-650 2 5.00
11 651-700
  Mild Severe
Mean Weight of Placenta 435.63 371.43
Maximum Weight of placenta 650.00 600.00
Minimum Weight of Placenta 250.00 200.00
Coefficient of variation 23.85 23.83
Standard Deviation 103.91 88.52

The mean placental weight was 495 grams in control group, 435.63 grams in mild hypertension and 371.43 grams in severe hypertension. Thus there is a significant lowering of placental weight in pregnancy induced hypertension. Placentae weighing less than 250 grams are found only in pregnancy induced hypertension. As severity of hypertension increases, placental weight decreases as confirmed by minimum placental weight of 250 grams in mild hypertension and 200 grams in severe hypertension. A significant increase in the incidence of intrauterine growth retardation and still birth is found with lower placental weight. Low birth weight is associated with low placental weight.

The relation between severity of pregnancy induced hypertension and mean placental weight is shown in Figure 2. From the figure it is observed that placental weight decreases with increase in severity of hypertension. Between placental weight and foetal weight, if the value of one is known, we can calculate the approximate value of the other with the help of equations given in Figure 3, 4 and 5 in control, mild pregnancy induced hypertension and severe pregnancy induced hypertension groups respectively.

From figure 3. it is clear that linear correlation exists between weight of newborn baby and the weight of placenta in the control group. This linear relationship is expressed by the following equation :

y = 2.0944 (x) + 1599.3 (1)

Where x is the weight of the placenta in grams any y is the weight of newborn baby in grams.

For mild (Figure 4) and severe (Figure 5) pregnancy induced hypertension cases also the relationship between weight of newborn baby and the weight of placenta is linear. For the mild pregnancy induced hypertension the relationship is given by the following equation :

y = 2.6625 (x) + 1322.7 (2)

Where x is the weight of the placenta in grams and y is the weight of newborn baby in grams.

For the severe pregnancy induced hypertension the relationship between weight of newborn baby and the weight of placenta is given by the following equation:

y = 2.8284 (x) + 998.02 (3)

Where x is the weight of the placenta in grams and y is the weight of newborn baby in grams. These equations can be used to estimate the weight of the newborn baby from the weight of the placenta.

Discussion :

Placenta being a foetal organ shares the same stress and strain, to which the foetus is exposed. Thus any disease process affecting the mother and foetus also has a great impact on placenta. Normally the placental morphology varies considerably during its short life span. Alterations in placenta as part of “Ageing” phenomenon are probably a part of maturation process and go hand in hand with continued growth of placenta. Placenta grows till 37th week and as a result immature villi are seen even till term. Hence in the study on placenta Fox (1975) has stressed the importance of analysing the placental pathology quantitatively and has stated that the importance of the lesions could be realized only when assessed in relation of foetal growth and maturation.

Hosemann (1949) in his study of normal term pregnancy found the placental weight of 400-1000 grams where as Wigglesworth (1962) found placental weight to be 360-570 grams. In the present study, the placental weight is found to range between 250-700 grams. Therefore, in the present study, the placental weights are lower than the findings of above authors. But the mean placental weight as seen in the present study (495 + 25 grams) is in conformity with the findings of Adair and Thelander (1925) Singh, Padmanabhan, Chinara, Negi and Singh (1979) and Williams, Bannister, Berry,collins, Dyson, Dussek and Ferguson (1995) viz. 400-500, 475 and 500 grams respectively.

Chakravorty (1967) in his study of pregnancy induced hypertension found the mean placental weight of 410 grams in mild hypertension and 350 grams in severe hypertension. Mean placental weight in pregnancy induced hypertension as seen in present study is 435 + 25 grams in mild hypertension and 371 + 25 grams in severe hypertension and is in conformity with the findings of above author.

Chakravorty (1967) found mean foetal birth weight 2805 grams in the normal term pregnancy, 2724 grams in mild hypertension and 1759 grams in severe hypertension. In the present study, mean foetal birth weight is 2640 grams in mild hypertension. Therefore, in the present study, mean foetal birth weight is lower than the findings of the above author. The reduction in placental and foetal weight in pregnancy induced hypertension as shown by Armitage, Boyd, Hamilton and Rowe (1967), Chakravorty (1967) Thomson, Billewicz and Hytten (1969), Boyd and Scott (1985) and Garg, Rath and Sharma (1996) is also confirmed by the present study.

Sinclair (1948), Thomson et al. (1969), Hamilton and Girmes (1969), Mukerjee and Lal (1983), Vasudeva, Choudhary and Anand (1991) and Garg et al. (1996) have shown that there is a linear correlation between placental weight and foetal weight. This is also confirmed by the present study.

References :

  1. Adair, F. L. and Thelander, H. (1925): A study of the weight and dimensions of the human placenta in its relation to the weight of newborn infant. American Journal of Obstetrics and Gynaecology. 10. 172-205.
  2. Armitage, P; Boyd,J. D.; Hamilton W. J. and Rowe, B. C (1967) : A statistical analysis of a series of birth-weights and placental weight. Human Biology. 39 : 430.
  3. Boyd, P. A. and Scott, A. (1985) : Quantitative structural studies on human placentae associated with pre-eclampsia, essential hypertension and intrauterine growth retardation. British Journal of Obstetrics and Gynaecology : 92 : 714- 721.
  4. Chakravorty, A. P. (1967) : Foetal and placental weight changes in normal pregnancy and pre-eclampsia. Journal of Obstetrics and Gynaecology of British Commonwealth. 74 : 247-253
  5. Fox, H. (1975) : The morphological basis of placental insufficiency. Journal of Obstetrics and Gynaecology of India. 25 : 441-450.
  6. Garg. K.; Rath, G. and Sharma, S. (1996): Association of birth weight,placental weight and the site of umbilical cord insertion in hypertensive mothers Journal of Anatomical Society of India. 44. 4.
  7. Hamilton, W. J. and Girmes, D. (1969) : A statistical analysis of the growth of the human placenta correlated with the foetus. Journal of Anatomy. 105 : 204.
  8. Hosemann, H. (1946) : Duration of pregnancy and weight of the placenta. Archives of Gynaecology 176 : 453.
  9. Mukerjee, B and Lal, R. (1983) : Relation between foetal weight and placental size. Journal of Anatomical Society of India. 32 : 124-126.
  10. Sinclair, J. G. (1948) : Significance of placental and birth weight ratios. Anatomical Record. 102 : 245.
  11. Sinclair, J. G. (1948) : Placental-Foetal Weight ratios. Taxas Reproductive Biology and Medicine. 6 : 168.
  12. Singh, S.; Padmanabhan, R.; Chinara, P. K; Negi, B. B. and Singh, U. K. (1979) : Some observations on placentae from maternity hospitals in Varanasi. Journal of Anatomical Society of India. 28 : 31
  13. Thomson, A. M.; Billewicz, W. Z and Hytten, F. E. (1969) : The weight of the placenta in relation of birth weight. Journal of Obstetrics and Gynaecology of British Commonwealth. 76 : 865-872.
  14. Vasudeva, N.; Choudhary, R and Anand, C. (1991): Weight of the placenta, weight of the mother just before delivery and haemoglobin concentration of cord blood as an indicator to the weight of the newborn. Journal of Anatomical Society of India : 40 : 141.
  15. Wigglesworth. J.S. (1962) : The gross and microscopic pathology of the prematurely delivered placenta. Journal of Obstetrics and Gynaecology of British Commonwealth. 69 :934-943.
  16. Williams, P.L.; Bannister, L. H.; Berry,M.; Collins, P.; Dyson; M.; Dussek, J. E. and Ferguson, M. W. J. : Gray's Anatomy In: Early human Development, 38th Edn; Churchill Livingstone Edinburgh. London.P. 166 (1995).

J. Anat. Soc. India 50(1) 24-27 (2001)

Access free medical resources from Wiley-Blackwell now!

About Indmedica - Conditions of Usage - Advertise On Indmedica - Contact Us

Copyright © 2005 Indmedica