Conservative Management of a Monochorionic Twin Pregnancy with an Intrauterine Fetal Death at 20–21 Weeks and Successful Term Delivery of the Second Twin

Introduction

One of the obstetric complications of twin pregnancy is the intrauterine death of one fetus. The reported incidence is approximately 2.5% to 5.0% [1]. In Indonesia, the incidence is not clearly known, due to limited data availability. A death that occurs in the first trimester usually leads to fewer complications than a death in the second and third trimesters [2,3]. A primary therapeutic conundrum in obstetrics is presented by the antenatal mortality of one fetus in the second or third trimester of a twin pregnancy [4]. A second- and third-trimester single fetal death of a twin pregnancy is reported to increase the death, preterm birth, and neurological injury of the surviving co-twin. Although rare, it can trigger a coagulation defect in the mother as well [5,6]. Neurological morbidities are also more common in monochorionic twins than in dichorionic gestation [3,7,8]. Thus, a consideration of pregnancy termination might persist.

Case Report

A 31-year-old primigravid woman was referred from a secondary hospital for follow-up at the obstetrics policlinic due to suspected congenital anomaly on the second fetus at 18–19 weeks of gestation. At the first antenatal visit to our hospital, an obstetric ultrasound was performed, showing a monochorionic diamniotic pregnancy with hygroma colli, absence of diastolic flow, and 15% growth discordance on the second fetus. At 20 weeks, an obstetric ultrasound follow-up was performed, and the death of the second fetus was diagnosed. Good vitality was observed in the remaining fetus, and no morphological abnormalities were found. Magnetic resonance imaging was not performed, because it is not a routine procedure in our center. A laboratory examination showed that the prothrombin time and activated partial thromboplastin time were within normal limits 1 month afterward. The patient had ultrasound and non-stress test check-ups biweekly, with one laboratory examination performed until term. The results consistently demonstrated that the surviving fetus had adequate growth and vitality (Figure 1).

At 38 weeks of gestation, the patient was admitted to the maternity ward for induction of labor. An amount of 25 mcg of misoprostol was placed on the posterior fornix as labor induction. A pelvic examination was performed, and the cervix was favorable. Six hours later, misoprostol induction was evaluated with cardiotocography, and category III cardiotocograph was found. She ultimately delivered by cesarean delivery, due to fetal distress. There was no difficulty encountered during surgery. A single live female infant was born with poor muscle tone. The body weight was 2510 g, and after one cycle of ventilation, the APGAR score was 6 in 1 min and 8 in 5 min. The second baby was delivered afterward, resembling a mummified paper, with a body weight of 100 g and a body length was 15 cm. After observation, the first baby was hospitalized without oxygen support until discharged home 3 days after delivery. The baby was 3 months old at the time of this report, with normal growth and development, and had received mandatory immunization according to her age.

Discussion

This report demonstrates that in cases of a single fetal death in a twin pregnancy during the second trimester, conservative management can be successful. The prognosis of pregnancy following the loss of one fetus will be primarily based on the gestational age at the time of fetal death and chorionicity. A prior study investigated the likelihood of the surviving twin dying after the demise of a single fetus in uterus. The study found that the probability of death for monochorionic twins was 12% (95% CI 8–19%), whereas, for dichorionic twins, it was 4% (95% CI 2–7%) [7]. Moreover, following the death of one fetus, monochorionic twins had a 4.81-fold increased likelihood of experiencing neurodevelopmental morbidity (95% CI 1.39–16.6 P<0.05) [9].

The incidence of single fetal death in twin pregnancies is reported to be 2.5% to 5.0% [1]. Intrauterine single fetal death can occur at any gestational age. The surviving twin will most likely develop normally if the death happens during the first trimester of pregnancy. However, there was found to be a higher risk of preterm labor, intrauterine growth restriction, preeclampsia, and neonatal mortality if the fetal loss occurred after mid-gestation (17 weeks gestation) [2,3].

The frequency of single intrauterine death in twins is 0.5% to 6.8% in the second and third trimesters [3,10–12] and poses a higher risk of mortality and morbidity for the surviving twin [2,13,14]. In monochorionic pairs, the risk of death of the surviving co-twin or severe neurological injury is 30% to 50% and is significantly increased, compared with dichorionic pregnancies [3,7,8].

In theory, the death of one fetus could result in coagulation disorder in the mother. The surviving twin is delivered a few weeks after the death of a single fetus [6]. The rates of cerebral palsy amongst the surviving monochorionic co-twin are increased by a factor of 6 [15].

The effects of a single intrauterine fetal death on the surviving co-twin in a monochorionic diamniotic twin are explained by 2 different theories. First, the twin embolization theory [16] explains that through placental vascular anastomoses, thromboplastic proteins from the deceased twin are transmitted to the surviving fetus, causing disseminated intravascular coagulopathy and severe end-organ damage. This notion has been supported by post-mortem evidence of arterial occlusion.

Other evidence showed that the surviving co-twin’s neurological impairment occurs rapidly. The second theory, the transfusional theory, supports this phenomenon [17]. The systemic vascular resistance on the deceased twin’s chorion decreases relatively when one fetus dies. An acute transfusion from the survivor to the dead fetus occurs downstream due to the venovenous and arterio-arterial placental anastomoses. The central nervous system, as well as other critical and metabolically active organs, such as the renal and gastrointestinal systems, are hypo-perfused due to the resulting hypotension in the surviving twin [18]. This latter theory is supported by reports of fetal anemia in survivors and the acute timing of the brain injury [7,8,17]. In the present case, there was no fetal anemia found in the remaining fetus. We measured the peak systolic velocity of the middle cerebral artery and found the result of 33.12 cm/s.

The most dangerous complication after a single fetal death, which is said to happen 3 to 5 weeks later, is maternal coagulopathy. Although rare, the probable mechanism of maternal coagulopathy, which can be fatal for both the mother and the fetus, is the release of fibrin and thromboplastin from dead tissues into maternal circulation [19,20]. Therefore, carrying a pregnancy past week 5 is riskier and less common.

There is currently no agreement on how to proceed or what gestational age is optimum for terminating a pregnancy in twin pregnancy with single intrauterine death. Most twin pregnancies complicated by single fetal death go into spontaneous labor within the following weeks. D’Alton et al reported that most of the instances (approximately 90%) will result in delivery within 3 weeks of fetal death [21]. Another study reported a case of intrauterine death at 25 weeks, and the pregnancy was continued until 9 weeks later, at 34 weeks of gestation [5].

However, in other studies, the median time between the death of a single fetus and the delivery of the second twin was reported to be 5 weeks, 7 weeks, and 9 weeks. One of the longest reported pregnancies was a case from Stefanescu et al, which successfully continued for almost 12 weeks [20]. Another study reported that the longest a pregnancy could be continued was 7 weeks; however, the patient experienced preeclampsia, later maternal coagulopathy, and a stillbirth as a result [19]. Carlson and Towers stated that if lung maturity is achieved at 32 weeks, delivery should be considered [22].

In the present case, conservative management with close surveillance could be successful as an option to continue the pregnancy until term. To the best of our knowledge, this was the first study that reported conservative management of a single intrauterine death of more than 12 weeks.

The mode of delivery of the surviving co-twin was mainly vaginal delivery. In 1984, D’ Alton et al reported that 14 of 15 of his cases were delivered by cesarean delivery. Given that one twin had died due to the adverse intrauterine environment, and provided that the second twin was not much immature, cesarean delivery was advised to prevent additional harm [21]. However, a study by Bell et al demonstrated that an increase in cesarean delivery from 3.2% to 5.8% does not significantly lower infant death or morbidity [23]. Thus, single intrauterine death per se is not an indication of cesarean delivery [4].

Conclusions

Conservative management under close monitoring in monochorionic twin pregnancy with early second-trimester single fetal death could be the best option to obtain a favorable outcome until term. We recommend conservative management with close surveillance monitoring using non-stress tests after 32 weeks, biweekly ultrasound, and at least of one maternal coagulation profile test. A steroid should be given if indicated and if preterm delivery is anticipated before 34 weeks of gestation.