The Study On The Effects Of Twin Pregnancy On Uterine Pull Tension

Objective:To study on the effects of twin pregnancy on uterine pull tension, and the change of the uterine contractility in the oxytocin induced by concentration gradient. To discuss the effects of the uterine contractility when the uterine pull tension of twin pregnancy had changed.Materials and Methods: To collect the uterine smooth muscle of single and twin pregnant women in the second trimester of pregnancy(26±6W)and in the late pregnancy(37±6W), and make into 30 strips each groups. Maternal age was 28-34 years old. All of them were primipara.They delivered in hospital because of illness need to operation termination from 2014 October to 2015 March at the First Affiliated Hospital of Medical University Of Anhui Department of Obstetrics. All pregnant women had antenatal check regularly and normal amniotic fluid volume. The development of fetus and pregnant weeks consisitent. Induced by oxytocin(OT) concentration gradient, and observed the change of uterine pull tension of single and twin pregnancy and the effects of the uterine contractility. Get sample from every pregnant woman and make four muscle strips and compare the Muscle tension measured with the real quality according to system screenshot analysis and converse the muscle tension of a quality unit. Contraction of uterine smooth muscle is judged by contraction wave and its size. The experimental data were analyzed statistically by software SPSS 19. The measurement data were indicated as mean ± standard deviation( ±s). Mean among the groups adopt t test and count data were examined by χ2. The changing trend of uterine tension was tested by linear correlation and regression test. It’s statistically significant when P<0.05.Results:(1) In Krebs solution, the uterine pull tension of late single pregnancy was bigger than that in second trimester(9.542±0.503 g VS 6.025±0.637g), and the uterine pull tension of late twin pregnancy was bigger than that in second trimester(10.896±0.311 g VS 7.090±0.560g), and the uterine pull tension of second trimester of twin pregnancy was bigger than that of single pregnancy at the same time(7.090±0.560 g VS 6.025±0.637g), and the uterine pull tension of late twin pregnancy was bigger than that of single pregnancy at the same time( 10.896±0.311 g VS 9.542±0.503g). There was statistical significance(P<0.05).(2) When OT concentration was 100 M-10+1 M, the average uterine pull tension rose from 11.780 g to 24.230 g in the second trimester of single pregnancy, and rose from 13.402 g to 23.614 g in the late single pregnancy, and the rising of the uterine pull tension was the biggest, at this time(OT concentration of 10+1 M), the uterine contraction was the strongest. Induced by oxytocin(OT) concentration gradient, the appearance of uterine contraction wave was more early, and the peak was more high, and the frequency was more fast by the uterine pull tension change of the second trimester of single pregnancy. There was statistical significance(P<0.05).(3) When OT concentration was 100 M-10+1 M, the average uterine pull tension rose from 13.395 g to 24.490 g in the second trimester of twin pregnancy, and rose from 12.478 g to 18.414 g in the late twin pregnancy, the rising of the uterine pull tension was the biggest, at this time(OT concentration of 10+1 M), the uterine contraction was the strongest. Induced by oxytocin(OT) concentration gradient, the appearance of uterine contraction wave was more early, and the peak was more high, and the frequency was more fast by the uterine pull tension change of the second trimester of twin pregnancy. There was statistical significance(P<0.05).(4) When OT concentration was 100 M-10+1 M, the average uterine pull tension of single pregnancy rose from 13.402 g to 23.614 g at late pregnancy period and average uterine pull tension of twin pregnancy rose from 12.478 g to18.414 g at late pregnancy period.And the uterine pull tension increased mostly. When OT concentration was 10+1 M, the contraction of the uterus was the strongest. Moreover, the uterine pull tension change of late single pregnancy caused early appearance of uterine contraction wave with high frequency and fast wave when induced by OT concentration gradient. There was statistical significance(P<0.05).Conclusion:(1) By the progress of pregnancy of twin pregnancy, the uterine pull tension was enlarged, and the uterine contraction was declined.(2) The uterine pull tension of twin pregnancy was bigger than that of single pregnancy with the same gestational weeks, while the uterine contractility was more small.(3) The sensitivity of uterine smooth muscle of twin pregnancy was decreased to oxytocin.(4) In OT concentration of 100 M-10+1 M, the rising of the uterine pull tension was the biggest, at this time( OT concentration of 10+1 M), the uterine contractility was the strongest.