Fetal and Placental Weights in Experimentally Delayed Implantation Pregnancy

Hooverman, Lois L.; Meyer, Roland K.; Wolf, Richard C.

doi:10.1210/endo-86-1-131

Cited by 10 publications

(6 citation statements)

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“…The growth of the placenta is already terminated when the growth of the fetuses is still intensive, as has been shown in other studies [12,15,24,26], The placenta reaches a peak weight on day 20, whereas the most marked weight gain of the fetuses occurs between days 21 and 22. Beyond day 20 the placental weight decreases.…”

Section: Discussionsupporting

confidence: 66%

Intrauterine Dystrophy in Rats Due to Placental Insufficiency Caused by Hormonally Induced Prolonged Gestation

Bührdel¹,

Willgerodt²,

Keller³

et al. 1974

Neonatology

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The duration of pregnancy in rats can be prolonged beyond day 26 after conception by administration of synthetic gestagens. The fetal mortality increased with prolonged duration of gestation to 24.8% on day 24 and 54.6% on day 25. Nearly all the fetuses were dead on day 26. On day 24 some of the litter mates and on day 25 all of the living ones were markedly hypotrophic. A placental insufficiency is suggested as causing the increasing mortality and the hypotrophy of the fetuses. The placental weight increases up to the 20th day of gestation, decreases slightly thereafter and does so markedly beyond the 24th day. An increase of water content is characteristic for the postmature litter mates.

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Section: Discussionsupporting

confidence: 66%

Intrauterine Dystrophy in Rats Due to Placental Insufficiency Caused by Hormonally Induced Prolonged Gestation

Bührdel¹,

Willgerodt²,

Keller³

et al. 1974

Neonatology

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“…Ovariectomy in the rat followed by hormone replacement results in placental hypertrophy (9 11; 13, 17, 23, 26) associated with en hanced fetal growth (9,11,13). Similar results have been obtained in a series of studies in the rabbit by Abdul-Karim et al (1).…”

Section: Discussionsupporting

confidence: 65%

Fetal and Placental Growth in the Rat following Differential Reduction of Litter Size

Croskerry¹,

Smith²,

Hall³

et al. 1978

Neonatology

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The effects on fetal and placental growth of differential litter size reduction on day 10 (LR10) and day 13 (LR13) were determined in the rat. LR10 resulted in significant increments in placental weight, fetal body and brain weight, and brain protein content in the survivors at day 21. A marginal effect on brain cellularity (DNA) was observed. Values for these parameters generally followed the extent of reduction. Placenta weight was also related to original litter size. In contrast, LR13 which was associated with survival of supernumerary placentae (those without a fetus) produced no growth enhancement. Prenatal development was discussed in terms of general systemic influences and hormonal regulatory mechanisms.

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“…results]. Because delayed-implanted embryos may grow faster [13], our data certainly do not exclude that the surviving embryos had implanted later. However, because the pups of the hCG rats were born after a normal gestation length, the present data do not allow to conclude that the injection of hCG had delayed implantation for 1-2 days.…”

Section: Discussionmentioning

confidence: 89%

The Effect of a Single Dose of Human Chorionic Gonadotropin at Proestrus on Embryonic Mortality, Fetal Growth and Gestation Length in the Rat

Mattheij¹,

Heussen²,

Linssen³

et al. 1987

Gynecol Obstet Invest

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The noxious effect of a single dose of 20 IU human chorionic gonadotropin (hCG) given at proestrus on embryonic and fetal survival as well as on fetal weight was studied. Fetal survival varied between 43.6 and 67.6%; the mortality rate was highest before implantation. The surviving fetuses of rats treated with hCG between days 17 and 20 of pregnancy weighed significantly less than controls. Embryonic mortality and fetal growth retardation could be prevented by giving anti-hCG monoclonals 28 or 45 h after hCG administration, but not when anti-hCG was given 69 or 93 h after hCG. 5 IU hCG did not induce embryonic or fetal mortality. On the other hand, 80 IU hCG increased the mortality to 100%; this was entirely due to preimplantation loss. It is speculated that due to a long metabolic half-life of hCG, the steroid metabolism is disturbed, causing implantation failure and/or delay of implantation. By day 21 of pregnancy, however, the fetuses of the hCG treated rats had made up greatly for the growth retardation; they were born after a similar gestation length and with a similar birth weight as the pups of control rats.

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Fetal and Placental Weights in Experimentally Delayed Implantation Pregnancy

Cited by 10 publications

References 0 publications

Intrauterine Dystrophy in Rats Due to Placental Insufficiency Caused by Hormonally Induced Prolonged Gestation

Intrauterine Dystrophy in Rats Due to Placental Insufficiency Caused by Hormonally Induced Prolonged Gestation

Fetal and Placental Growth in the Rat following Differential Reduction of Litter Size

The Effect of a Single Dose of Human Chorionic Gonadotropin at Proestrus on Embryonic Mortality, Fetal Growth and Gestation Length in the Rat

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