British Journal of Obstetrics and Gynaecology March 1976. Vol 83. pp 251-253
EXTRA-AMNIOTIC PREGNANCY. A CASE REPORT BY
H. G. KOHLER AND
D. M. J E N K I N S The Maternity Hospital, Leeds LS2 9L W Summary A case of extra-amniotic pregnancy ending in premature labour at 35 weeks is reported.
EXTRA-AMNIOTIC pregnancy is believed to arise from rupture of the amniotic membrane early in pregnancy whilst the chorion remains intact. It thus differs from extra-membranous pregnancy in which both chorion and amnion rupture long before term, usually in the first or early second trimester (Kohler et al, 1970). Very few cases of extra-amniotic pregnancy are recorded in the literature and these are reviewed by Torpin (1968). According to him, isolated rupture of the amniotic membrane leads to the formation of fibrous strands between the retracting amnion and the intact chorion. These strands, usually designated as amniotic bands, are known to cause circumferential constriction of limbs and digits (Leading Article, 1973). The constriction, if severe, may lead to necrosis of the distal portion, which eventually separates-so-called spontaneous intrauterine amputation. Accordingly, the problem of extra-amniotic pregnancy has almost exclusively been considered in conjunction with extremital defects, or other lesions of the ‘amniotic band syndrome’. A case record of unquestionable extra-amniotic pregnancy is presented, in which no membranous strands, nor any injuries to the infant that could have been caused by them, were found, and in which premature labour occurred.
two years earlier, had been complicated by mild hypertension. Labour had started spontaneously at 36 weeks. Nothing abnormal was recorded in respect of the amniotic fluid or rupture of membranes. Delivery, by forceps, produced a normally formed live male infant with a birth weight of 2570 g. The placenta was recorded as healthy, weighing approximately 600 g. In the early neonatal period the infant became jaundiced, but was discharged on the tenth day with his mother. On the next day he was diagnosed as having gastro-enteritis and admitted to the local fever hospital where he gradually improved. The causal organism was never identified. The present pregnancy was supervised from 16 weeks and no significant antenatal complications were observed. Labour commenced spontaneously in the 35th week. The first stage lasted nearly 12 hours and at full dilatation of the cervix the membranes were ruptured artificially. Clear amniotic fluid escaped; its quantity did not seem abnormal. The second stage lasted two minutes and resulted in the normal delivery of a live male infant weighing 2220 g who showed no gross abnormality. The third stage lasted three minutes. When the afterbirth, which weighed 560 g, was examined by one of us, an apron-like membranous structure was found around the cord insertion (Fig. 1). The possibility of this ‘apron’ representing the amniotic membrane was con-
CASEHISTORY The mother was 19 years old at the time of her second delivery. The first pregnancy, nearly 25 1
252
KOHLER AND JENKINS
FIG.1 Placenta with retracted amniotic membrane (‘apron’) around insertion of umbilical cord.
sidered, but not readily accepted because the lining of the membranous sac seemed to be normal and did not give the impression of being denuded. Histological examination, however, proved beyond doubt that the amniotic lining of the sac was absent (Fig. 2), and that the ‘apron’ consisted of amniotic membrane only (Fig. 3). There were no strands attached to the ‘apron’, nor was any other significant lesion found in the placenta. It was clear that the fetus had developed within the unlined chorionic sac. The infant seemed to develop normally, but had an attack of ‘snuffles’ on the eighth day, became febrile and eventually developed pneumonia and septicaemia due to Streptococcus faecalis. On antibiotic and ventilator treatment he made a slow recovery.
COMMENT No episode or event during this pregnancy was recorded that might have been associated with rupture of the amnion, in particular, there was
no history of external trauma, no suspicion of any attempt at self-induced abortion, and no convincing evidence of pelvic infection. The time of the rupture is thus unknown; judging by the size of the retracted amniotic membrane. and allowing for shrinkage, it might have occurred before or around mid-pregnancy. Extra-amniotic pregnancy was in this case associated with premature labour, an association which was probably coincidental, particularly as the first pregnancy also ended prematurely at 36 weeks. It seems unlikely that the infant’s severe infection during the late neonatal stage was directly related to extra-amniotic pregnancy. No evidence of intrauterine infection was found on histological examination of placenta and membranes. The fact that extra-amniotic pregnancy is easily overlooked suggests that it may be more common than is indicated by the number of published reports. In particular, cases like the present one in which the infant showed no
EXTRA-AMNIOTIC PREGNANCY
253
FIG.3 Section through ‘apron’ showing that it consists of amniotic membrane. The arrow indicates the layer of amniotic epithelium. ( x 100.)
spective diagnosis was made in one case in our files (Kohler et al, 1970).
FIG.2 Section through membranous sac. The arrow indicates the chorion denuded of amnion. Decidual spaces are seen at the lower portion of the microphotograph. ( x 100.)
ACKNOWLEDGEMENTS We are indebted to Miss M. Roberts and her colleagues of the Labour Ward staff for conscientiously saving and labelling all placentas delivered in this hospital, and especially for sparing the amniotic membranes.
evidence of the ‘amniotic band syndrome’, are likely to go unnoticed. We are strengthened in this belief by our experience of extra-membranous pregnancy, which also was reputed to the diagnosis Of a be very uncommon ; typical case in 1968, a further four cases were detected in subsequent years, and a retro-
REFERENCES Kohler, H. G., Peel, K. R.,and Hoar, R. A. (1970): Journal of Obstetrics and Gynuecology of the British Commonwealth, 77, 809. Leading Article (1973): British Medical Journal, 3, 651. Torpin, R. (1968): Fetal Malformation Caused by Amnion Rupture During Gestation. Charles Thomas, Springfield.
EXTRA-AMNIOTIC PREGNANCY. A CASE REPORT BY
H. G. KOHLER AND
D. M. J E N K I N S The Maternity Hospital, Leeds LS2 9L W Summary A case of extra-amniotic pregnancy ending in premature labour at 35 weeks is reported.
EXTRA-AMNIOTIC pregnancy is believed to arise from rupture of the amniotic membrane early in pregnancy whilst the chorion remains intact. It thus differs from extra-membranous pregnancy in which both chorion and amnion rupture long before term, usually in the first or early second trimester (Kohler et al, 1970). Very few cases of extra-amniotic pregnancy are recorded in the literature and these are reviewed by Torpin (1968). According to him, isolated rupture of the amniotic membrane leads to the formation of fibrous strands between the retracting amnion and the intact chorion. These strands, usually designated as amniotic bands, are known to cause circumferential constriction of limbs and digits (Leading Article, 1973). The constriction, if severe, may lead to necrosis of the distal portion, which eventually separates-so-called spontaneous intrauterine amputation. Accordingly, the problem of extra-amniotic pregnancy has almost exclusively been considered in conjunction with extremital defects, or other lesions of the ‘amniotic band syndrome’. A case record of unquestionable extra-amniotic pregnancy is presented, in which no membranous strands, nor any injuries to the infant that could have been caused by them, were found, and in which premature labour occurred.
two years earlier, had been complicated by mild hypertension. Labour had started spontaneously at 36 weeks. Nothing abnormal was recorded in respect of the amniotic fluid or rupture of membranes. Delivery, by forceps, produced a normally formed live male infant with a birth weight of 2570 g. The placenta was recorded as healthy, weighing approximately 600 g. In the early neonatal period the infant became jaundiced, but was discharged on the tenth day with his mother. On the next day he was diagnosed as having gastro-enteritis and admitted to the local fever hospital where he gradually improved. The causal organism was never identified. The present pregnancy was supervised from 16 weeks and no significant antenatal complications were observed. Labour commenced spontaneously in the 35th week. The first stage lasted nearly 12 hours and at full dilatation of the cervix the membranes were ruptured artificially. Clear amniotic fluid escaped; its quantity did not seem abnormal. The second stage lasted two minutes and resulted in the normal delivery of a live male infant weighing 2220 g who showed no gross abnormality. The third stage lasted three minutes. When the afterbirth, which weighed 560 g, was examined by one of us, an apron-like membranous structure was found around the cord insertion (Fig. 1). The possibility of this ‘apron’ representing the amniotic membrane was con-
CASEHISTORY The mother was 19 years old at the time of her second delivery. The first pregnancy, nearly 25 1
252
KOHLER AND JENKINS
FIG.1 Placenta with retracted amniotic membrane (‘apron’) around insertion of umbilical cord.
sidered, but not readily accepted because the lining of the membranous sac seemed to be normal and did not give the impression of being denuded. Histological examination, however, proved beyond doubt that the amniotic lining of the sac was absent (Fig. 2), and that the ‘apron’ consisted of amniotic membrane only (Fig. 3). There were no strands attached to the ‘apron’, nor was any other significant lesion found in the placenta. It was clear that the fetus had developed within the unlined chorionic sac. The infant seemed to develop normally, but had an attack of ‘snuffles’ on the eighth day, became febrile and eventually developed pneumonia and septicaemia due to Streptococcus faecalis. On antibiotic and ventilator treatment he made a slow recovery.
COMMENT No episode or event during this pregnancy was recorded that might have been associated with rupture of the amnion, in particular, there was
no history of external trauma, no suspicion of any attempt at self-induced abortion, and no convincing evidence of pelvic infection. The time of the rupture is thus unknown; judging by the size of the retracted amniotic membrane. and allowing for shrinkage, it might have occurred before or around mid-pregnancy. Extra-amniotic pregnancy was in this case associated with premature labour, an association which was probably coincidental, particularly as the first pregnancy also ended prematurely at 36 weeks. It seems unlikely that the infant’s severe infection during the late neonatal stage was directly related to extra-amniotic pregnancy. No evidence of intrauterine infection was found on histological examination of placenta and membranes. The fact that extra-amniotic pregnancy is easily overlooked suggests that it may be more common than is indicated by the number of published reports. In particular, cases like the present one in which the infant showed no
EXTRA-AMNIOTIC PREGNANCY
253
FIG.3 Section through ‘apron’ showing that it consists of amniotic membrane. The arrow indicates the layer of amniotic epithelium. ( x 100.)
spective diagnosis was made in one case in our files (Kohler et al, 1970).
FIG.2 Section through membranous sac. The arrow indicates the chorion denuded of amnion. Decidual spaces are seen at the lower portion of the microphotograph. ( x 100.)
ACKNOWLEDGEMENTS We are indebted to Miss M. Roberts and her colleagues of the Labour Ward staff for conscientiously saving and labelling all placentas delivered in this hospital, and especially for sparing the amniotic membranes.
evidence of the ‘amniotic band syndrome’, are likely to go unnoticed. We are strengthened in this belief by our experience of extra-membranous pregnancy, which also was reputed to the diagnosis Of a be very uncommon ; typical case in 1968, a further four cases were detected in subsequent years, and a retro-
REFERENCES Kohler, H. G., Peel, K. R.,and Hoar, R. A. (1970): Journal of Obstetrics and Gynuecology of the British Commonwealth, 77, 809. Leading Article (1973): British Medical Journal, 3, 651. Torpin, R. (1968): Fetal Malformation Caused by Amnion Rupture During Gestation. Charles Thomas, Springfield.
