Interstitial Pregnancy in the Third Trimester with Severe Preeclampsia: A Case Report and Literature Review

Abstract

An interstitial pregnancy that continues beyond the second trimester is a rare phenomenon. We report a patient with an interstitial pregnancy undiagnosed until the third trimester. A multiparous woman was referred to us because of preeclampsia at 26 weeks of gestation. The placental position was the right fundus, and color Doppler ultrasound revealed myometrial thinning and subplacental hypervascularity, leading to a suspicion of placenta accreta spectrum (PAS). Emergency cesarean section was performed at 281/7 weeks of gestation due to severe preeclampsia. The right tubal horn to the isthmus of the fallopian tube bulged with placental adhesion and a part of the tube had ruptured, with the omentum adhering to the ruptured part. Interstitial and tubal isthmic pregnancy with uterine rupture was diagnosed.

Diagnosis pitfall of interstitial pregnancy: a case report of a term pregnancy with abnormal placentation

“…This case report shows a term interstitial pregnancy with abnormal implantation of the placenta. In a study published in 2020 [ 2 ], the authors report 6 term interstitial pregnancies, one of which developed with preeclampsia and the others had no specific event in their in pregnancy course. Also, there are reports of abnormal placentation in this condition.…”

“…Focusing on the operative management of IP, especially the retained tissues, the benefit of hysteroscopy is recently confirmed by using morcellation techniques to avoid some complications [ 12 ]. Organizing managements for term or late IPs, Nagayama et al in a literature review presented term IPs that were managed mostly by supracervical hysterectomy [ 2 ]. Also, in other case reports of coexistence of the morbid placenta adherence with interstitial pregnancy, it is suggested to manage this category by surgical techniques using hysterectomy as well as segmental resection or medical therapy using methotrexate [ 3 – 6 ].…”

“…Interstitial pregnancy (IP) is defined as a kind of ectopic pregnancy in which the pregnancy product is implanted in the intramural fragment of the tube. It is estimated that it accounts for less than 3% of ectopic pregnancies [ 1 , 2 ]. Although it may remain asymptomatic in the first 14–16 weeks of pregnancy [ 3 ], it is mostly ruptured after the first trimester that leads to massive hemorrhage due to high vascularity [ 4 ].…”

“…Considering to this fact, there are few reports of full-term interstitial pregnancies [ 4 , 5 ]. Also, there is likelihood of the presence of abnormal placentation in this category of ectopic pregnancy that make this condition more complicated[ 2 , 4 , 5 ]. The rarity of this case report is delivery a full term misdiagnosed interstitial pregnancy complicated by placenta increta.…”