The Impact of Maternal Body Mass Index and Gestational Age on the Detection of Uterine Contractions by Tocodynamometry: A Retrospective Study

OBJECTIVE

To examine the impact of maternal body mass index (BMI) and gestational age (GA) on uterine contraction detection by tocodynamometry.

METHODS

Gravidas with preterm labor (PTL) complaints who were evaluated by tocodynamometry, discharged from Labor and Delivery triage, and subsequently readmitted for preterm delivery were studied. Forty-six patients in whom contractions were detected (group 1) were compared to 49 women in whom contractions were not detected (group 2) with respect to BMI and GA at both evaluation and delivery. Multivariable logistic regression was used to adjust for confounders.

RESULTS

Group 2 had a higher mean BMI (31.7 vs 26.1, P < .001), were more likely to be obese (57.1% vs 19.6%, P < .001), and were more likely to have been evaluated in the mid-trimester (36.7% vs 17.4%, P = .04) compared to group 1. Independent risk factors for the inability of the tocodynamometer to detect contractions were obesity (odds ratio [OR] 0.18, 95% confidence interval [CI] 0.07-0.46) and evaluation in the mid-trimester (OR 0.33, 95% CI 0.13-0.84).

CONCLUSION

Our study provides evidence that the effectiveness of tocodynamometry diminishes with increasing maternal BMI. Efficacy of tocodynamometry is also decreased at earlier GA, most pronounced below 25 weeks. To evaluate women with PTL symptoms in the mid-trimester or symptomatic obese women at any GA, a modality other than tocodynamometry could be valuable to more accurately assess uterine activity.

Intra- and inter-individual differences in human sperm DNA methylation

There is growing evidence that sperm DNA methylation is important in maintaining proper sperm health and function. Previous studies have associated sperm DNA methylation levels with sperm quality and function, however, little is known regarding the intra- and inter-individual variability in sperm methylation levels. This study characterizes this variation. Sperm epigenetic differences between successive semen samples from 12 patients were examined to identify the intra- and inter-individual differences globally across the genome, and in specifically defined genomic regions using the Illumina Infinium HumanMethylation450 BeadChips. Methylation analysis identified a bimodal distribution in the methylation levels that were non-uniformly distributed across the different genomic regions. The methylation levels were highly correlated in both the intra- and inter-individual comparisons. The intra-individual methylation levels were more highly correlated than the inter-individual comparison both globally and across the defined genomic regions, demonstrating that sperm DNA methylation levels are relatively stable between semen sample collections.

Estimation of the 6-digit level allele and haplotype frequencies of HLA-A, -B, and -C in Koreans using ambiguity-solving DNA typing

Because Korean society is fast becoming multi-ethnic, the determination of ambiguous human leukocyte antigen (HLA) types using HLA allele frequencies is becoming less applicable. In this study, we focused on the development of new technical methods to directly resolve the ambiguities arising from HLA genotyping. One hundred and fifty unrelated healthy Korean adults were included in this study. All alleles from each HLA locus were first divided into 2-4 groups, with each group amplified in a single PCR tube (multi-group-specific amplification, MGSA). To resolve phase ambiguities, some allele groups were also amplified separately in small group-specific amplification (SGSA) tubes. In order to then resolve incomplete sequence ambiguities, primers for MGSA and SGSA were initially designed to cover additional exons. If needed, a heterozygous ambiguity resolving primer (HARP) or sequence specific primer (SSP) was also used. When MGSA and SGSA methods were applied, the rate of phase ambiguity was greatly reduced to an average of 6% (1.3% in HLA-A, 15.7% in -B, and 2.0% in -C). Additional HARP and SSP methods could resolve all the phase ambiguities. Using our proposed method, we also detected three alleles that have not been previously reported in Korea, C*04:82, C*07:18, and C*08:22, and report 6-digit level HLA allele and haplotype frequencies among Koreans. In conclusion, the use of MGSA/SGSA for the initial amplification step is a cost-effective method facilitating timely and accurate reporting, given the continuing increase in the ethnic diversity of the Korean population. The MGSA described here can be applicable to various populations and thus could be shared by the majority of HLA typing laboratories. However, efforts to solve HLA ambiguity should continue, because SGSA, HARPs and SSPs would be specific to a particular population.