Superfœtation : à propos d’un cas et revue de la littérature

Superfetation and heterotopic pregnancy: Case report of two rare phenomena coexisting and implications in the era of assisted reproductive technologies

Key Clinical Message

To raise awareness about the increasing incidence of superfetation and heterotopic pregnancy in patients with ovarian induction, their insidious symptoms of abdominal pain, anemia, and hemodynamic instability in early pregnancy, and the usefulness of transvaginal ultrasound (TVUS) and quantitative beta human chorionic gonadotrophin (b-hCG) for diagnosis.

Abstract

Superfetation, occurrence of ovulation, fertilization, and implantation during an ongoing pregnancy and heterotopic pregnancy (HP) simultaneous presence of intrauterine and extrauterine pregnancies are infrequent phenomena. We report a case where both coexisted, challenges in diagnosis and management and association with the widespread use of assisted reproductive technologies (ARTs). A 32-year-old woman, who previously underwent ovulation induction therapy, presented with abdominal pain at 8 weeks pregnancy according to her last menstrual period. The patient had high quantitative serum beta-human chorionic gonadotropin (b-hCG) (30,883 mIU/mL). She was vitally stable and not anemic. Transvaginal ultrasound (TVUS) revealed two pregnancies at different gestational ages: an intrauterine pregnancy at 5 weeks and 3 days, and a right intact tubal ectopic pregnancy at 10 weeks and 5 days. Superfetation resulting in HP was then diagnosed. Subsequently, the patient underwent right laparoscopic salpingectomy. The intrauterine pregnancy progressed normally, resulting in delivery of a healthy full-term neonate via Cesarean section at 38 weeks. Superfetation is typically rare from suppression of follicular development and ovulation during pregnancy. Various theories have been proposed to explain its etiology, including polyovulation, delayed blastocyst implantation, and abnormal estrogen and b-hCG surges. In superfetation, an embryo resulting from a previous conception coexists with another embryo, either intrauterine, resulting in diamniotic dizygotic twins with significantly different gestational ages, or extrauterine resulting in HP. Despite being particularly challenging to diagnose because its presenting symptoms can overlap with those of other more common clinical conditions in early pregnancy, HP is increasingly seen with ARTs. In addition, the treatment of HP is versatile, ranging from expectant management to laparoscopic surgery. High level of suspicion for HP and superfetation is crucial in patients who, after ART, present with abdominal pain, hemodynamic instability, or anemia. Additionally, patients planning to undergo subsequent ART cycles should be thoroughly screened with b-hCG and TVUS to exclude an ongoing intrauterine or extrauterine pregnancy.

Twins Separated at Birth: Across a Country and Around the World/Twin Research: Memorial Tribute to Isaac Blickstein, MD; Infanticide and Sacrifice of Archaic-Aged Twins and Triplets; Prehistoric Twin Burials; Highlights from a Conference on Three Identical Strangers/Media Reports: An Atypical Twin Father; An Actor's Twin Brother; Twin Link to Tulsa, Oklahoma Massacre; Superfetated Twins; Twin Comedians and Script Writers; Indian Twins' Loss to COVID-19

Every reared-apart monozygotic (MZ) twin pair offers a fresh perspective on human developmental questions. This is true regardless of whether the co-twins were raised in the same country or across the globe. The members of two pairs of separated MZ female twins have recently come to attention. In one case the twins were raised by different families in Argentina; in the other case the twins were raised by different families in Sweden and Vietnam. The perceptions and perspectives of these twins are insightful. The twin research section that follows begins with a tribute to our late esteemed colleague, Dr Isaac Blickstein (1953-2020). Research concerning the infanticide and sacrifice of Archaic-aged twins and triplets and prehistoric twin burials is reviewed next. Highlights from a conference focused on the 2018 film Three Identical Strangers are also included in this portion. The final section of this article includes media reports of an atypical twin father, an actor's twin brother, a twin link to the 1921 Tulsa, Oklahoma massacre, the birth of superfetated twins, twin comedians and script writers and Indian twins' tragic loss to COVID-19.

Unpredicted ovulations and conceptions during early pregnancy: an explanatory mechanism of human superfetation

In this bioessay, a literature review on human superfetation was performed in order to find epidemiological variables associated with this phenomenon. Thereafter, an explanatory mechanism of superfetation compatible with the endocrinological, histological and physiological changes undergone by women during early pregnancy is proposed. Superfetation can be defined as the ovulation, fertilisation and implantation of a second or additional embryo(s) during pregnancy. The literature review evidences a small discordance in gestational age between dizygotic twins in humans (range: 2–4 weeks; mean ± s.e.m.: 3.3 ± 0.3 weeks). This difference is compatible with a luteal out-of-phase (LOOP; i.e. atypical increase in E2 levels in the mid-luteal phase)-like event occurring between 1 and 3 weeks after the ovulation that allowed the first pregnancy to take place. The LOOP-like event may allow passive sperm transport from the vaginal fornix to the Fallopian tube ipsilateral to the ovulatory ovary and trigger a LH peak and ovulation. Furthermore, during very early pregnancy, the decidual reaction is not yet completed and at least one proximal Fallopian ostium may be opened, allowing the passage of the spermatozoa ascending to the fertilisation site and the extra embryo(s) descending to the implantation site(s).

Acute stress may induce ovulation in women

BACKGROUND

This study aims to gather information either supporting or rejecting the hypothesis that acute stress may induce ovulation in women. The formulation of this hypothesis is based on 2 facts: 1) estrogen-primed postmenopausal or ovariectomized women display an adrenal-progesterone-induced ovulatory-like luteinizing hormone (LH) surge in response to exogenous adrenocorticotropic hormone (ACTH) administration; and 2) women display multiple follicular waves during an interovulatory interval, and likely during pregnancy and lactation. Thus, acute stress may induce ovulation in women displaying appropriate serum levels of estradiol and one or more follicles large enough to respond to a non-midcycle LH surge.

METHODS

A literature search using the PubMed database was performed to identify articles up to January 2010 focusing mainly on women as well as on rats and rhesus monkeys as animal models of interaction between the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes.

RESULTS

Whereas the HPA axis exhibits positive responses in practically all phases of the ovarian cycle, acute-stress-induced release of LH is found under relatively high plasma levels of estradiol. However, there are studies suggesting that several types of acute stress may exert different effects on pituitary LH release and the steroid environment may modulate in a different way (inhibiting or stimulating) the pattern of response of the HPG axis elicited by acute stressors.

CONCLUSION

Women may be induced to ovulate at any point of the menstrual cycle or even during periods of amenorrhea associated with pregnancy and lactation if exposed to an appropriate acute stressor under a right estradiol environment.