12 Week 4 Day Baby Heart Rate 134 Boy or Girl

J Matern Fetal Neonatal Med. Author manuscript; available in PMC 2017 Mar ane.

Published in final edited form equally:

PMCID: PMC4679415

NIHMSID: NIHMS696725

First trimester fetal heart rate every bit a predictor of newborn sexual practice ^*

L. A. Bracero

^oneSection of Obstetrics and Gynecology, West Virginia University, Charleston Campus, Charleston, WV, United states of america

D. J. Seybold

ⁱⁱCenter for Health Services & Outcomes Research, Charleston Area Medical Center Health Educational activity and Research Institute, Charleston, WV, USA

Southward. Witsberger

ⁱⁱCenter for Health Services & Outcomes Enquiry, Charleston Area Medical Center Health Teaching and Enquiry Plant, Charleston, WV, United states of america

L. Rincon

²Center for Health Services & Outcomes Research, Charleston Area Medical Centre Health Instruction and Research Institute, Charleston, WV, Usa

A. Modak

ⁱⁱCenter for Health Services & Outcomes Enquiry, Charleston Expanse Medical Eye Health Instruction and Enquiry Found, Charleston, WV, The states

L. V. Baxi

^threeDepartment of Obstetrics and Gynecology, New York University Langone Medical Middle and Schoolhouse of Medicine, New York, NY, U.s.

Abstract

Objective

To predict the sex activity of newborns using first trimester fetal heart charge per unit (FHR).

Methods

This was a retrospective review of medical records and ultrasounds performed between 8 and 13 weeks of gestation. Continuous variables were compared using Student's t-tests while categorical variables were compared using Chi-square test.

Results

Nosotros found no significant differences between 332 (50.7%) female and 323 (49.3%) male person FHRs during the first trimester. The hateful FHR for female fetuses was 167.0 ± 9.1 bpm and for male person fetuses 167.3 ± 10.1 bpm (p = 0.62). There was no significant difference in crown rump length between female and male person fetuses (4.01 ± 1.7 versus iii.98 ± ane.seven cm; p = 0.78) or in gestational age at nascency (38.01 ± 2.1 versus 38.08 ± 2.i weeks; p = 0.67). The males were significantly heavier than females (3305.3 ± 568.3 versus 3127.v ± 579.eight m; p < 50.0001) simply there were no differences in the proportion of small for gestational age (SGA), average for gestational age (AGA) and large for gestational age (LGA) infants.

Conclusions

We institute no pregnant difference between the female person and male person FHR during the showtime trimester in dissimilarity to the prevailing lay view of females having a faster FHR. The only statistically significant difference was that males weighed more female person newborns.

Keywords: Fetal heart charge per unit, fetal sex, first trimester, newborns, ultrasound

Introduction

Expectant parents are frequently curious and request fetal sex identification. Ultrasound (U.s.a.) during the second and third trimesters can be reliably used to determine the sex activity of the fetus. The accuracy of U.s.a. before 14 weeks gestation in identifying the sexual practice of the fetus is poor [1]. There is a prevailing belief in the general population that the female fetus has a more rapid eye rate than the male fetus. Nosotros found ane website that encourages prospective parents to use fetal heart rate (FHR) to predict the sex of newborns [two]. The purpose of this study was to address this issue during the first trimester of pregnancy when US is often inaccurate in identifying the fetal sex. Our null hypothesis was that in that location is no significant difference in FHRs between female and male fetuses during the first trimester.

Methods

This is a written report of births at Women and Children's Hospital from Jan 1, 2006 to Apr nine, 2010 in which USs were performed betwixt eight and thirteen weeks of gestation at the hospital'south Perinatal Diagnostic Center. The medical records and USs of these patients were retrospectively reviewed. The inclusion criteria were: singleton pregnancies with documented FHR that delivered at our infirmary and had pregnancy dating by a terminal menstrual period (LMP) and a confirmatory crown rump length (CRL) measurement or had an uncertain LMP and were dated past the initial CRL. The exclusion criteria were: maternal bradycardia or tachycardia, maternal thyroid affliction, maternal cardiac arrhythmias, maternal use of beta blocker agents, maternal anxiety disorder, maternal fever, spontaneous abortion, stillbirths, ambiguous genitalia at nascence, fetal malformations, fetal cardiac arrhythmias and fetal chromosomal abnormalities. The Institutional Review Board of the Charleston Area Medical Center approved the study.

US examinations were performed using Acuson Sequoia (Mountain View, CA), Aloka Blastoff 10 (Tokyo, Nihon) and General Electric Voluson E8 (Rancho Cordova, CA) machines. The Acuson Sequoia motorcar was equipped with 4.0–viii.0 MHz abdominal and vaginal transducers. The Aloka Blastoff 10 machine was equipped with 3.0–7.5 MHz abdominal and 3.5–vii.v MHz vaginal transducers. The General Electric Voluson E8 machine was equipped with 2.0–v.0 MHz abdominal and iv.0–nine.0 MHz vaginal transducers. The fetal heart rate was obtained using spectral Doppler ultrasound for 4–5 centre beats while keeping the thermal index for soft tissues and bone as low as possible (<1) in accordance with the Every bit Low As Reasonably Doable (ALARA) principle. The sex was established at the time of birth.

Descriptive statistics and univariate analyses were used as appropriate for continuous or chiselled variables. Continuous variables were presented as means and standard deviations and were compared by using Student'south independent samples t-tests. Categorical variables were reported as percentages and were compared using Chi-square or Fisher'south exact test. An alpha of less than 0.05 was used equally a determinant of statistical significance.

We calculated a sample size based on the data from McKenna et al. [3]. They found that during the starting time trimester, male fetuses had a slightly higher average FHR when compared to female person fetuses (154.9 ± 22.8 bpm versus 151.vii ± 22.7 bpm; p = 0.13). We determined that the enrollment for the current written report should be 1600 pregnant women with a goal of including 794 males and 794 females based on a FHR deviation of 3.2 beats per minute (bpm) between the male and female fetuses and an alpha level of 0.05 with 80% power. We planned to have an over enrollment to provide adequate numbers for each gender since the delivery charge per unit for females is slightly lower at 49.five% than for males. Statistical assay was done using SAS 9.3 (SAS Found, Cary, NC).

Results

An interim assay was performed subsequently data on 655 patients were collected. The study was stopped considering there was a very small-scale absolute difference between the sexes (0.3 bpm). We calculated that it would require a sample size of over 12 000 participants to detect a significant deviation in FHR and this led united states to believe that there would be no statistically significant difference between the FHR of female and male fetuses.

Our study population consisted of 655 mothers and their fetuses. The hateful maternal age was 24.2 ± 6.0 years, ethnicity was primarily white (91.two%) and the majority were multiparous (57.iii%). Additional maternal characteristics and nascence consequence comparisons between male person and female person newborns are shown in Tabular array 1. The main Usa indication was for an uncertain or unknown LMP (37.7%). We institute no significant differences between 332 (50.7%) female and 323 (49.3%) male person FHRs during the first trimester. The mean FHR for female fetuses was 167.0 ± 9.0 bpm and for male fetuses 167.3 ± 10.ane bpm (p = 0.62). Besides, a breakdown of FHR by 8, 9, 10, 11, 12 and 13 weeks showed no difference in FHR between the sexes (Figure i). The CRL was likewise not significantly different between the female and male person fetuses (iv.01 ± 1.7 cm versus three.97 ± 1.6 cm; p = 0.78) and neither was gestational historic period at nascence (38.0 ± 2.1 weeks versus 38.ane ± 2.i weeks; p = 0.67). The male person newborns were significantly heavier than the females (3305.3 ± 568.3 g versus 3127.5 ± 579.8 1000; p < 0.001) with no differences in the proportion of small-scale for gestational historic period (SGA), average for gestational historic period (AGA) and large for gestational historic period (LGA) infants. The FHR for male person versus female fetuses that were built-in SGA (163.9 ± 8.i bpm, n = 14 versus 164.i ± 12.0 bpm, n = 14; p = 0.4411), AGA (167.5 ± ten.5 bpm, n = 232 versus 166.seven ± 9.three bpm, northward = 229; p = 0.3434), LGA (162.4 ± 12.5 bpm, due north = 5 versus 168.vii ± 11.half dozen bpm, n = 3; p = 0.5088) and preterm (166.1 ± 10.9 bpm, n = 48 versus 168.8 ± 9.5 bpm, north = 51; p = 0.1813) was not statistically significantly different during the showtime trimester. The rate of preterm births (<37 weeks gestation) was like for both male person and female sexes; 14.9% for males and fifteen.7% for female newborns (p = 0.78). The FHRs for male and female fetuses that were subsequently admitted to the Neonatal Intensive Care Unit (NICU) were also not statistically significantly different during the offset trimester (165.0 ± 8.6 bpm, n = 18 versus 167.1 ± viii.6 bpm, due north = 24; p = 0.4411).

Male and female heart charge per unit by gestational historic period.

Table 1

Pregnancy characteristics and birth outcomes of male person and female person newborns.

	Male (n = 323) Northward (%) or mean ± SD (range)	Female (n = 332) N (%) or mean ± SD (range)	p value
Maternal age at delivery	24.6 ± six.1 (13–43)	23.7 ± 6.0 (11–47)	0.0884
Ethnicity/race			0.4572
White	297 (91.95%)	300 (90.36%)
Black/African American	25 (7.74%)	28 (8.43%)
Asian American	1 (0.31%)	four (1.20%)
Nulliparity	134 (41.49%)	146 (43.98%)	0.5284
Ultrasound indication			0.0817
Uncertain/unknown LMP	123 (38.08%)	124 (37.35%)
Abdominal pain/cramping	57 (17.65%)	48 (14.46%)
Vaginal bleeding	23 (seven.12%)	47 (xiv.16%)
Maternal illness (DM, HTN)	31 (ix.sixty%)	41 (12.35%)
Nuchal translucency	32 (9.91%)	28 (eight.43%)
Fetal viability	24 (7.43%)	21 (6.33%)
Large or small for dates	27 (8.36%)	18 (5.42%)
Nausea/vomiting	half-dozen (ane.86%)	5 (1.51%)
Crown rump length	iii.97 ± 1.vi	4.01 ± 1.7	0.7835
Gestational historic period at birth (weeks)	38.one ± two.1 (24–42)	38.0 ± 2.1 (28–41)	0.6688
Weight of fetus (g)	3305.3 ± 568.three (660–4935)	3127.5 ± 579.8 (940–4770)	<0.001

Discussion

The topic of FHR and gender prediction has been studied more often than not during the third trimester of pregnancy. Many of these studies have involved small sample sizes and the results have been mixed. Some studies were washed during the antepartum period, others during early on labor and all the same others during late labor. Bernard [4] studied 45 female and l male fetuses weekly during the last eight weeks of pregnancy and constitute no differences in the mean FHR betwixt the sexes. Hall et al. [5] assigned sex activity to 100 fetuses at 32 weeks gestation using averaged FHR recordings from previous prenatal visits. Female sex activity was assigned if the FHR equaled or exceeded 140 bpm and male sexual activity was assigned if the FHR was less than 140 bpm. They constitute the FHR to exist a good forecaster of the newborn's sex, reporting a positive predictive value of 91% for males and 74% for females. Ostler and Sun [6] reported on a convenient sample of 20 pregnancies that had a single FHR obtained with a Doppler fetoscope after the 26th calendar week of gestation. The women gave nascence to 10 male person and 10 female infants. They used the 140 bpm FHR cutting-off to predict the sex of the newborn. They written report a sensitivity of x% and specificity of 60% for predicting males and a sensitivity of sixty% and specificity of 10% for predicting females. Petrie and Segalowitz [7] studied 250 female and 250 male fetuses during early labor and found that the hateful difference in the FHR betwixt them was not statistically significant. Dawes et al. [8] analyzed the FHR records of 1884 term pregnancies, 890 female and 994 male fetuses, during the last hour prior to delivery. They institute that female fetuses spent more time with FHR >150 bpm while male fetuses spent more fourth dimension with FHR <120 bpm (p <0.0001). Arguably, other variables affect the FHR during labor.

Druzin et al. [9] performed non-stress tests on 12 female fetuses and 25 male fetuses between 19 and forty weeks of gestation. They reported no differences in baseline FHR between the female and male fetuses. Genuis et al. [x] followed 212 singleton pregnancies between fourteen and 41 weeks gestation with antepartum FHR testing. They computed the overall FHR averages for each pregnancy and institute no significant difference between the antenatal FHRs of male and female fetuses during the 2nd and 3rd trimesters of pregnancy. There is one abstract publication comparison male and female person FHRs during the second trimester. Neiger et al. [11] reported on the FHR of 57 male and 43 female fetuses between 18 and 23 weeks of gestation. The fetal sex was identified by ultrasound examination. In that location was no significant divergence in the average FHR between the male and female fetuses.

McKenna et al. [3] analyzed the FHR obtained at less than fourteen weeks gestation co-ordinate to the sex of the fetus. They found no significant differences between the 244 female person and 233 male FHRs studied. The average FHRs in our study for both male and female fetuses were higher and the standard deviations were lower than those they reported. The departure between our offset trimester FHRs for male person infants (167.three ± 10.1, n = 323 versus 154.9 ± 22.8, n = 233; p = 0.0001) and for female infants (167.0 ± 9.i, n = 332 versus 151.7 ± 22.7, north = 244; p = 0.0001) was statistically significantly higher when compared to the results reported by McKenna and colleagues. They included patients beneath 14 weeks gestation but did non provide the actual gestational historic period ranges. Information technology is possible that they included pregnancies at half dozen–vii weeks gestation when the FHRs are known to be lower when compared to pregnancies between 8 and 14 weeks of gestation [12].

Male person newborn infants at term on boilerplate are known to weigh 150 g more than than female person newborns [xiii]. We institute that our male person newborns weighed 178 m more female newborns. Leicester [fourteen] while working in Republic of india reported on the FHR of 550 term or near term simple pregnancies before labor or during the early stages of labor. He divided the population into Europeans, Natives of India and Eastward Indians (mixed European and Native). He found no significant difference betwixt the average FHR of male person and female newborns. He also looked at the influence of fetal weight on FHR, since the FHR differences between the sexes accept been based on the assumption that the FHR is inversely related to the fetal weight. In the Native grouping the boilerplate FHR diminished equally the weight of the newborn increased. Yet, he did non find a similar human relationship in the European and East Indian groups. He reported that the fetal weight has some influence on the rate of the fetal eye. Coughlin [15] reviewed the medical charts of 233 women who gave birth to 123 male and 110 female infants. The average FHRs betwixt the sexes was not significantly different. Like us, she found that males weighed more than female newborns (3428 g versus 3221 m, p = 0.001) but there was no significant human relationship between tertiary trimester FHR and newborn weight. Bernard [iv] also institute no relationship betwixt the average FHR during the last 8 weeks of pregnancy and the size of the newborns. In our population, there was no significant difference in the size of the fetuses equally adamant by the fetal CRL measurements during the commencement trimester when our FHR measurements were obtained.

The forcefulness of our study is that it excluded patients with maternal and fetal conditions that could have influenced the FHR. We included merely FHRs between 8 and thirteen weeks gestation when the FHR is more uniform. Nosotros analyzed the FHR by the distinct gestational ages as well as in aggregate. Nosotros also analyzed the FHR based on outcomes, such as preterm births, NICU admissions, SGA, AGA and LGA infants.

In determination, we found no meaning differences between female person and male FHR during the first trimester. Therefore, expectant parents should non rely on starting time trimester FHR to make up one's mind the sexual activity of their baby.

Footnotes

^*Presented at the 22nd Earth Congress on Ultrasound in Obstetrics and Gynecology, 9–12 September 2012, Copenhagen, Denmark.

Declaration of interest

The authors report no declaration of interest.

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12 Week 4 Day Baby Heart Rate 134 Boy or Girl

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4679415/

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