GUINEA PIG FETUS DOES NOT CHANGE ITS PRESENTATION DURING SECOND HALF OF GESTATION
Abstract
Objectives: The aims of this paper are: 1. To investigate spontaneous changes in fetal presentation during the second half of gestation in guinea pig fetus, 2. to observe provoked changes of fetal presentation, by passive positioning fetus into an upside-down position and “sitting” position. Eight fetuses from singleton pregnancies were included. Experimental design: Ultrasound examinations (Toshiba Nemio SSA-550A apparatus) were started on the 26th day of gestation (GD). Each fetus was examined 2-3 times in each 5-day interval until the end of gestation. First the spontaneous orientation of fetus was determined by tracking along the longitudinal and transversal axes of the fetus with the ultrasound probe. Then the fetus was brought into a head-down position relative to gravity for 5 minutes. The examination was repeated with the fetus in the head-up position. Results: In the period from the 26th – 30th GD in 7 of 21 observations spontaneous changes of presentation were observed. From the 31st GD all 133 observations were negative regarding spontaneous changes of presentation and situs. The chi-squared test showed that difference in spontaneous changes of presentation and situs before versus after 30th day of gestation had a statistical significance (χ² = 25.16 p <0.05). Frequency of ultrasound examinations before and after 30th day of gestation was not statistically significant (Fisher exact chi square p = 0.46, p >0.05). Fetuses were brought into a head-down and head-up 154 times. In none of these attempts did a fetus change presentation during the five minutes of observation. Conclusion: Guinea pig fetuses do not spontaneously or at provocation change presentation after 30th GD.
Key words: fetal presentation; gestation; guinea pig; ultrasound
PLODOVI MORSKIH PRAŠIČKOV NE SPREMENIJO LEGE V DRUGI POLOVICI BREJOSTI
Namen prispevka je: 1. raziskati spontane spremembe v legi plodu v drugi polovici brejosti pri plodovih morskih prašičkov; 2. opazovati vzpodbujene spremembe lege plodov v položaj od zgoraj-navzdol in v »položaju sedenja«.V raziskavo je bilo vključenih osem plodov iz ene brejosti. Z ultrazvočnimi pregledi (aparat Toshiba Nemio SSA-550A) smo pričeli 26. dan brejosti. Vsak plod je bil pregledan 2-3-krat v 5-dnevnih razmikih do konca brejosti. Najprej je bila ugotovljena spontana orientacija plodu z določanjem njegove vzdolžne in prečne osi z ultrazvočno sondo. Potem je bil plod za 5 minut obrnjen v položaj z glavo navzdol, sorazmerno s težo. Pregled plodu je bil ponovljen v položaju z glavo navzgor. V obdobju od 26. do 30. dneva brejosti smo v 7 od 21 opazovanj opazili spontane spremembe lege plodu. Od 31. dneva brejosti dalje pri vseh 133 opazovanjih ni bilo opaziti spontanih sprememb lege plodu. Analiza Hi-kvadrat je pokazala, da je razlika v spontanih spremembah lege plodu pred in po 30. dnevu brejosti statistično značilna (χ² = 25,16 16 p <0,05). Pogostnost ultrazvočnih preiskav pred in po 30. dnevu brejosti ni bila statistično značilna (Fisherjev natančni Hi-kvadrat test p = 0,46). Plodovi so bili postavljeni v položaj z glavo navzdol in navzgor 154- krat. V nobenem od teh poskusov ni prišlo do spontane spremembe lege plodu med petminutnim opazovanjem. Ti rezultati torej kažejo, da plodovi morskih prašičkov ne spremenijo lege spontano ali po provokaciji po 30. dnevu brejosti.
Ključne besede: sprememba lege plodu; brejost; morski prašiček; ultrazvok
References
(1) Sekulic SR. Possible explanation of the cephalic and noncephalic presentation during pregnancy: a theoretical approach. Med Hypotheses 2000; 55: 429–4.
(2) Sekulić SR, Mikov A, Petrović D. Probability for breech presentation and its significance. J Mater Fetal Neonatal Med 2010; 23: 1160–4.
(3) Kalbe P, Schultz J. Neonatological aspects of the anterior presentation of the calf. Tierärztl Prax K 2000; 28: 9–11.
(4) Sekulić S, Naumović N, LukaÄ D, et al. Ultrasound assessment of the effect of fetal position on the supine to prone righting reflex in guinea pig fetus. Period Biol 2010; 112: 97–104.
(5) Sekulic S, Kekovic G, Filipovic D, et al. The progressive increase of the longest episode of spontaneous movements in the guinea pig fetus within the first eleven days after the appearance of its first movements. Arc Biol Sci 2013; 65: 1459–62.
(6) Boos R, Hendrik HJ. Schmidt W. Behavior of fetal position in the 2d half of pregnancy in labor with breech and vertex presentations Geburtshilfe Frauenheilkd 1987; 47: 341–45.
(7) Miller EC, Kouam L. Frequency of breech presentation during pregnancy and on full term. Zentral Gynekol 1981; 103: 105–9.
(8) Reimers TJ, Dziuk PJ, Bahr J, et al. Transuterine embryonal migration in sheep, anteroposterior orientation of pig and sheep fetuses and presentation of piglets at birth. J Anim Sci 1973; 37: 1212–7.
(9) Scanlon PF. Orientation of cattle fetuses in utero in relation to stage of pregnancy. J Dairy Sci 1975; 58: 571–3.
(10) Scanlon PF. Orientation of sheep fetuses in-utero in relation to stage of pregnancy. J Anim Sci 1976; 42: 1217–9.
(11) Sekulic S, Bozic A, Zarkov M, et al. Changes in the anterior presentation in sheep fetuses due to their ventro-sacral position in the second half of gestation. Philipp J Vet Med 2012; 49: 51-6.
(12) Avery GT. Responses of foetal guinea pigs prematurely delivered. Genet Psychol Monogr 1928; 3: 245–331.
