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Objective:To study the relationship between maternal hemoglobin concentration, anemia rate in the third trimester and the altitudes, pregnancy outcomes among pregnant women in Tibet rural areas.Methods:This prospective study collected clinical and laboratory data of 390 Tibetan pregnant women who delivered after 28 gestational weeks at Chaya People's Hospital, Changdu city, Tibet autonomous region, from May 2020 to March 2021. Blood routine examination was performed at admission and 24-72 h postpartum using an automatic hematologic analyzer. According to the hemoglobin standard adjusted for altitude by World Health Organization (WHO), the association between pregnancy outcomes and maternal hemoglobin levels and anemia rate before and after adjustment were analyzed using Mann-Whitney U one-way analysis of variance, Chi-square, Pearson correlation, and Spearman correlation tests. Results:(1) In these women, the mean actual hemoglobin concentration in the third trimester was (121±16) g/L, and the prevalence of anemia and microcytic hypochromic anemia was 23.8% (93/390) and 20.3% (79/390), respectively. (2) After adjustment, the mean hemoglobin concentration was (93±17) g/L, and the prevalence of anemia and microcytic hypochromic anemia was 84.4% (329/390) and 30.5% (119/390), respectively. (3) Actual hemoglobin levels showed an increasing tendency as the altitude rose. At the altitude of 3 000-3 500 m, >3 500-4 000 m, and >4 000 m, the mean hemoglobin levels were (118±15) g/L, (119±17) g/L, and (124±16) g/L, respectively ( Ftrend=7.38, P=0.007). However, the prevalence of anemia and microcytic hypochromic anemia did not differ significantly between different altitude ( P>0.05). (4) Corrected hemoglobin levels were negatively associated with the altitude ( r=－0.31, P<0.001). At the altitude of 3 000~3 500 m, 3 500~4 000 m and >4 000 m, the mean corrected hemoglobin levels were (100±15) g/L, (92±17) g/L, and (87±18) g/L, respectively ( Ftrend=30.36, P<0.001). The prevalence of anemia increased with altitude ( χ2trend=15.44, P<0.001), but no association was observed between microcytic hypochromic anemia and altitudes ( P>0.05). (5) No association was found between actual or corrected anemia in the third trimester and adverse pregnancy outcomes, nor the hemoglobin level before or after adjustment and neonatal birth weight. Conclusions:In Tibet rural areas, the mean actual hemoglobin level in pregnant women tends to increase with the altitude. However, the prevalence of anemia and microcytic hypochromic anemia remains high and more attention should be paid to iron supplementary during pregnancy. After adjusting hemoglobin concentration based on WHO standard, more women were diagnosed as having anemia during pregnancy in this area, and the applicability of the diagnostic criteria for Tibetan residents requires further investigations.
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Objective To investigate the intrauterine growth characteristics of twins and birthweight discordant twins (discordant twins ).MethodsTotal of 1010 twin pregnancies (2020 fetuses) with complete delivery records from the Department of Obstetrics and Gynecology,the First and Third Affiliated Hospital of SUN Yat-sen University between January 1,2000 and July 31,2010 were studied retrospectively.One handred and ninteen cases (238 fetuses) with intrapair birthweight difference ≥25％ were determined as the discordant twins group,and the other 891 cases (1782 fetuses) with intrapair birthweight difference ＜ 25％ were identified as the concordant twins group.The singleton control group included 4042 singleton pregnancies in the same period.Results ( 1 ) Comparison of clinical data between the twins groups:the birthweight of larger-twin,smaller-twin and intrapair birthweight difference in the discordant twins group and the concordant twins group were ( 2090± 827 ) g,( 1392 ± 592 ) g,( 33.9 ±9.3 ) ％,and ( 2408 ± 543 ) g,( 2191 ± 505 ) g,( 8.9 ± 6.5 ) ％,respectively,with significant differences (P＜0.01).The incidence of discordant twins was 11.78％ (119/1010).Compared with the concordant twins group,the discordant twins group bad higher proportion of monochorionic twins,and higher prevalence of pregnancy complications such as late miscarriage,abnormal umbilical insertion,twin-twin transfusion syndrome and hypertensive disorders in pregnancy ( P ＜ 0.05 ).( 2 ) The characteristics of twin birthweight distribution:① In all the 2020 twins,80.05％ (1617/2020) fetuses had birthweight below the 50th percentile of the singleton control group,while 23.71％ (479/2020) feeuses got birthweight below the 10th percentile of the singleton control group.② After 19th gestational week,the 50th and 90th percentile of all twins' birthweight were lower than those of singletons.After 38th gestational week,the birthweight of singletons kept increasing and reached its peak at 41 th week,while the birthweight of twins reached its peak at 38th week,followed by a decline at 39 weeks,which was even lower than the 10th percentile of the singleton control group.③ The distribution of birthweight of larger- and smaller-twin in the discordant twins group:65 (54.6％,65/119) larger-twins and one (0.8％,1/119) smaller-twin had birthweight above the 50th percentile of all twins,while 5 (4.2％,5/119) larger-twins and 97 ( 81.5％,97/119 ) smaller-twins got birthweight below the 10th percentile of all twins.Conclusions ( 1 ) The patterns of birthweight curves for each gestational week are different between twins and singletons.In order to evaluate the growth of twins, birthweight reference for twins shoull be employed.( 2 ) According to the reference of twins birthweight,the most discordant twins are complicated with fetal growth restriction at least in one twin.
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ObjectiveTo investigate the clinical features of the abnormal chromosome karyotypes in twin pregnancies complicated with fetal malformations. Methods Totally 181 twin pregnancies (362 fetuses) in which one or two fetuses had abnormalities diagnosed by ultrasound were referred to the First Affiliated Hospital of Sun Yat-Sen University from January, 2000 to September, 2010. They were divided into different groups according to ( 1 ) maternal age: the cases with maternal age ≥35 were divided into advanced pregnancy group ( 105 fetuses) , and those with maternal age ＜35 were divided into young pregnancy group (203 fetuses) ; ( 2 ) conceived method : those conceived by assisted reproductive technology were divided into assisted reproductive group (81 fetuses), and the natural conception pregnancies were divided into natural conception group (227 fetuses) ; ( 3 ) chorionicity: the monochorionic twin (MCT) pregnancies were divided into MCT group( 123 fetuses), and the dichorionic twin (DCT) pregnancies were divided into DCT group( 185 fetuses); (4) structural abnormalities: 205 fetuses with structural abnormalities were divided into the abnormal fetal group, and 103 fetuses without structural abnormalities were divided into the normal fetal group. All fetuses were examined by the ultrasound and chromosomes were examined in 308 fetuses. Results( 1 ) The karyotype of fetuses: among 181 twin pregnancies, 23 cases had chromosomal abnormalities in 1 or 2 fetuses ( 12. 7％ ,23/181 ), and chromosomes were exarmined in both fetuses in 20 of 23 cases. Twenty-six of 308 fetuses were found with abnormal chromosomes ( 8.4％, 26/308 ) , and the aneuploid was the most common type of abnormal karyotypes ( 53.8％ , 14/26 ). Twenty-one of 205 fetuses with malformations were found with abnormal karyotypes (10. 2％, 21/205 ). (2) Seven of 123 fetuses in MCT group were with abnormal karyotypes (5.7％, 7/123), and 19 of 185 fetuses in DCT group were with abnormal karyotypes ( 10. 3％, 19/185 ). There was no statistical difference of abnormal chromosome incidence between the two groups. There were 14 fetuses with aneuploid in DCT group ( 7.6％, 14/185 ) ;but there was no fetus with aneuploid in MCT group. There was statistical difference between these two groups. In two cases of DCT group, only one fetus with malformation received chromosome examination because another fetus was dead, and the karyotypes were trisomy 21 and trisomy 18 respectively. Both fetuses of the rest 17 cases received chromosome examination, and the chromosomes of both fetuses in each pregnancy were different. Fifteen of 19 fetuses with abnormal chromosomes in DCT group were complicated with structural abnormalities, and 7 fetuses of 4 twin pregnancies in MCT group were with chromosomal abnormalities. (3) The comparison of the abnormal karyotype incidence between the advanced pregnancy group and young pregnancy group: the abnormal karyotype incidence of the advanced pregnancy group was 7. 6％ (8/105), and that was 8.9％ (18/203) in young pregnancy group. There was no statistical difference between the two groups ( P ＞ 0. 05 ). Six of 105 fetuses in advanced pregnancy group were aneuploids (5. 7％, 6/105), and 8 of 203 fetuses in young pregnancy group were aneuploids (3.9％, 8/203). The aneuploid incidence in advanced pregnancy group was significantly higher than that in young pregnancy group ( P ＜ 0. 05 ). (4) The comparison of the abnormal karyotype incidence between the assisted reproductive group and the natural conception group: 11 of 81 fetuses were with the abnormal karyotypes in assisted reproductive group ( 13. 6％, 11/81 ), and 15 of 227 fetuses were with the abnormal karyotypes in assisted reproductive group (6. 6％, 15/227). There was statistical difference between the two groups ( P ＜0. 05). There were 7 fetuses with the aneuploid in assisted reproductive group ( 8. 6％, 7/81 ) and 7 fetuses with the aneuploid in natural conception group ( 3. 1％, 7/227 ), which showed no statistical difference ( P ＞0. 05 ).(5) The comparison of the abnormal karyotype incidence between the abnormal fetal group and normal fetal group: 21 of 205 fetuses in abnormal fetal group were with abnormal karyotypes (10. 2％, 21/205), and 5 of 103 fetuses in normal fetal group were with abnormal karyotypes ( 4. 9％, 5/103 ) . There was no statistical difference (P ＞ 0. 05 ). 13 fetuses in abnormal fetal group were with the aneuploid (6. 3％, 1 3/205), and only one fetus in normal fetal group was aneuploid (1.0％, 1/103 ). There was statistical difference between the two groups ( P ＜ 0. 05 ). ConclusionsAneuploid is the most common abnormal karyotype in twin pregnancy complicated with fetal abnormalities, especially trisomy 21. Aneuploid mainly occurs in only one fetus of DCT, and chromosomal discordance is usually found in DCT. While in MCT, the twin fetuses with the same abnormal karyotype may have different pbenotypes. The results suggest that it is necessary to analyze both karyotypes of twins even if only one fetus is complicated with structural abnormalities.
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Objective To evaluate the effectiveness and safety of invasive procedures of prenatal diagnosis for twin gestations through analysing the results and outcomes of twins.Methods Invasive prenatal diagnostic procedures guided by ultrasound were introduced to 164 twin pregnancies with various indications,including 111 amniocentesis,and 53 cordocentesis.The results of prenatal diagnosis,complications and outcomes of these twins were analyzed with Chi-square test or Fisher's exact test.Results (1) Chromosome was examined in 261 fetuses and 6.13% (16/261)had abnormal karyotypes.(2) Comparing amniocentesis with cordocentesis,the fetal loss rate within two weeks after the procedure were 0.00% (0/191) and 3.85% (3/78),respectively (P=0.024).The total fetal loss rate and preterm delivery rates in amniocentesis and cordocentesis group were 3.87% (6/155) and 5.45% (3/55),51.22% (42/82)and 38.71% (12/31),respectively (P=0.235and 0.618).(3) Selective feticide was performed on 18 cases after prenatal diagnosis.Fifteen cases had survival neonates,two cases suffered from spontaneous abortion,and two cases had preterm labor with neonatal death.Conclusions (1) Invasive prenatal diagnostic procedures are effective and feasible in twins.Amniocentesis is a relative safer and simpler alternative to cordocentesis,which demanding higher skill and carrying higher fetal loss rate.(2) Mid-trimester selective feticide after prenatal diagnosis appears safety.Before the procedure,the chorionicity and fetal condition should be considered,in order to choose suitable feticide procedures.
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Objective To investigate the antenatal influencing factors associated with birth weight of twins and the risk factors for the occurrence of discordant twins. Methods Totally, 834 twins delivered at the Third Affiliated Hospital from January 2000 to December 2009 and the First Affiliated Hospital of SUN Yat-sen University, from January 2000 to June 2009, were recruited in the study. The diagnosis criteria of discordant twins was intrapair birth weight difference more than 25 %.Antenatal factors on birth weight were retrospectively investigated among twins and discordant twins respectively with Logistic analysis. Results (1) There were several factors associated with birth weight of twins, including maternal age, conceptive style, chorionicity, gestational diabetes mellitus and placental cord insertion ( P = 0. 021, 0. 000, 0. 000, 0. 012 and 0. 017, respectively). While hypertensive disorder in pregnancy, parity and fetal gender differences were not associated with the birth weight of twins (P＞0.05). Hypertensive disorder in pregnancy (OR=2. 600, 95% CI:1. 566-4. 316) and monochorionicity (OR= 1. 833, 95% CI: 1.010-3. 582) were risk factors of discordant twins. All 834 twin pregnancies were divided into 4 groups according to materal age, ＜25 yrs (n=69), 25-30 yrs (n=312), 30-35 yrs (n=325) and ≥35 yrs (n=128). The average birth weight of twins were (2205±483) g, (2347±406) g, (2381±439) g and (2352±455) g. Significant difference was found bewteen every two groups (P＜0. 05) except that between the 30-35 yrs and ≥35 yrs group (P＞0.05). Among twins of different gender (n=270), the average birth weight of boys and girls were (2416±-514) g and (2322±488) g, and that of female twins (n=272) and male twins (n=292) were (2301±418) g and (2381±428) g. Significant difference was shown between every two groups (P＜0.05) except that between the male twins and male fetus of twins of different gender (P＞0.05).Conclusions The fetal birth weight of twins decreases remarkably when maternal age ＜25, or monochorionicity twins, or complicated with marginal or velamentous placental cord insertion or female pairs.However, birth weight of twins would increase if the pregnancy conceived by assisted reproductive technology or complicated with gestational diabetes mellitus. Twin pregnancy complicated with hypertensive disorder in pregnancy or monochorionicity should alert the clinicians of discordance twins.