Monochorial diamniotic dizygotic twins in a German Shepherd Dog: A case report

Abstract

A 6.5-year-old clinically healthy German Shepherd Dog with regular oestrous cycles of 6 months was presented for pregnancy diagnosis on day 38 after ovulation (p.ov.). Ultrasonography revealed three individual placental sites in progressed resorption and two vital adequately developed foetuses sharing a joint placenta. On days 41 and 48 p.ov., sonographic signs indicated normal development of both foetuses, but on day 52 p.ov., both foetuses were found to be dead. A caesarean section was performed the same day. Examination of the removed uterus confirmed the diagnosis of a "twin" pregnancy with two foetuses sharing the same placental site but separate amniotic membranes. One foetus showed generalized oedema (anasarca). Bacterial culture of swabs taken from inside the placental cavity was negative. At histological examination of the uterus, no signs of inflammation were found. Serum relaxin concentrations (day 38, 41, 48 and 52. p.ov.) were consistent with those of bitches with normal pregnancies. Cytogenetic analysis of the two foetuses revealed dizygotic twins, one male and one female according to SRY-PCR. By genotyping 17 high-polymorphic canine microsatellites, it could be demonstrated that the two foetuses developed from two different oocytes.

Prenatal Diagnosis of Canine and Feline Twins Using Ultrasound: A Retrospective Study

“…In case 4C, the partial twisting of the umbilical cord occurred in a twin, and, in case 5C and 6C, the asynchronous and synchronous foetal deaths of the twins were observed. Foetal death and anasarca have been already documented in canine twins [20].…”

“…Prenatal diagnoses, using ultrasound, of monochorionic twins have been reported in dogs [20,21], but never in cats. However, monochorionic twins have been described macroscopically in dogs at birth [37][38][39].…”

“…Normal foetal development can be assessed by observing the chronologic relationship between organ development and gestation, which is also useful for determining the date of delivery [10][11][12][13][14][15][16], and embryonic/foetal disorders can be predicted by observing a delay in the time of development of the organs or alterations in their appearance, or by finding a slow rate of foetal growth [17][18][19]. Single reports of foetal abnormalities diagnosed early using ultrasound have been reported, both in canine and feline species, including monochorionic twins [20,21], hydrops fetalis [22][23][24][25][26][27][28], hydrocephalus [29,30], clefts [31], and kidney defects [32].…”

“…A general rule exists in the field of obstetrics according to which monochorionic twins are almost exclusively monozygotic [33]. However, monochorionic dizygotic twins have been reported in humans after assisted reproductive technologies [34] and in dogs [20]. On the other hand, dichorionic dizygotic twins are the norm, and dichorionic monozygotic twins are extremely rare [35].…”

The mystery of monozygotic twinning II: What can monozygotic twinning tell us about Amyoplasia from a review of the various mechanisms and types of monozygotic twinning?

“…Trauma, temperature, irradiation, starvation, chemical imbalance, and physical separation of blastocoel cells can all produce MZ twins (Aston et al, 2008). Double‐yolked eggs and two‐headed reptiles and amphibians are seen “in the wild,” and even conjoined domestic animals have been reported, but essentially all normally occurring twins (or other multiples) in animals are the result of polyovulation (e.g., more than one ova is ovulated and then successfully fertilized): cow (Hashiyada, 2017; Jiang et al, 2019; Klein et al, 2006; Shojaei Saadi et al, 2017; Song et al, 2012; Taylor & Murray, 1991), dog (Hogenboom, 2016; Joonè et al, 2016, 2017; Moura et al, 2017; Urhausen et al, 2017), fish (Samarin et al, 2015), frog (Tokmakov & Sato, 2019), horse (Govaere et al, 2009), lemur (St Clair et al, 2014), monkey (Schramm & Paprocki, 2004), mouse (Freund et al, 2013; Kitami & Nadeau, 2002; McLaren et al, 1995), pig (Corner, 1922; Kim et al, 2019; Park et al, 2019; Zhang et al, 2018), polar bear (Malenfant et al, 2016), rabbit (Bomsel‐Helmreich & Papiernik‐Berkhauer, 1976; Orgebin‐Crist, 1968; Shaver & Carr, 1967), salmon (Ytteborg et al, 2010), sheep (Celi et al, 2007), and starfish (Limatola et al, 2019). Some of the recent works in animals are related to “overripe ova” and how to improve the outcome of old eggs (Jiang et al, 2019; Kim et al, 2019; Song et al, 2012; Tokmakov & Sato, 2019).…”