1
|
Trends in Dizygotic and Monozygotic Spontaneous Twin Births During the Period 2007-2017 in Lombardy, Northern Italy: A Population-Based Study. Twin Res Hum Genet 2022; 25:149-155. [PMID: 35765814 DOI: 10.1017/thg.2022.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, we analyzed the estimated frequency of monozygotic (MZ) and dizygotic (DZ) spontaneous twins in Lombardy during the period 2007-2017. This is a population-based study using the regional healthcare utilization databases of the Lombardy Region. The total number of spontaneous twin deliveries, in separate strata of like and unlike sex, was obtained. Moreover, estimates of DZ and MZ twin births were calculated using Weinberg's method. The standardized rates (SRs), adjusted for maternal age, of DZ and MZ twin births were computed according to calendar period. The twinning rates were calculated among strata of parity and maternal age. Finally, DZ:MZ ratio was calculated. Among the 734,278 spontaneous deliveries, 9176 (12.5 out of 1000 births) couples of twins were identified. In the three periods considered (i.e. 2007-2010, 2011-2014 and 2015-2017), no trend in the SRs of MZ twins was observed, respectively 0.41 (95% CI [0.40, 0.43]), 0.43 (95% CI [0.42, 0.45]) and 0.43 (95% CI[0.42, 0.45]). Differently, a slightly decreasing trend was observed in DZ twins SRs, respectively 0.87 (95% CI [0.84, 0.89]), 0.81 (95% CI [0.79, 0.83]), and 0.78 (95% CI [0.76, 0.80]). As concerns parity and maternal age, the rate of DZ twin births was consistently higher in nulliparae women aged 35 years or more. In our cohort, despite the increase of maternal age, a decline of spontaneous twin births emerged, especially due to the downward trend of DZ twins.
Collapse
|
2
|
Farley GJ, Sauer MV, Brandt JS, Ananth CV. Singleton pregnancies conceived with infertility treatments and the risk of neonatal and infant mortality. Fertil Steril 2021; 116:1515-1523. [PMID: 34620455 DOI: 10.1016/j.fertnstert.2021.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 07/29/2021] [Accepted: 08/04/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVES To examine the risks of neonatal and infant mortality in relation to infertility treatment and to quantify the extent to which preterm delivery mediates this relationship. DESIGN Cross-sectional study. SETTING United States, 2015-2018. PATIENT(S) A total of 14,961,207 pregnancies resulting in a singleton live birth. INTERVENTION(S) Any infertility treatment, including assisted reproductive technology and fertility-enhancing drugs. MAIN OUTCOME MEASURE(S) Neonatal (<28 days) mortality. The effect measure, risk ratio (RR), and 95% confidence interval (CI) were derived from log-linear Poisson models. A causal mediation analysis of the relationship between infertility treatment and mortality associated with preterm delivery (<37 weeks) was performed. The effects of exposure misclassification and unmeasured confounding biases were assessed. RESULT(S) Any infertility treatment was documented in 1.3% (n = 198,986) of pregnancies. Infertility treatment was associated with a 51% increased risk of neonatal mortality (RR 1.51, 95% CI 1.39-1.64), with a slightly higher risk for early neonatal mortality (RR 1.57, 95% CI 1.43-1.73) than late neonatal mortality (RR 1.33, 95% CI 1.11-1.58). These risks were similar for pregnancies conceived through assisted reproductive technology and fertility-enhancing drugs. The mediation analysis showed that 72% (95% CI 59-85) of the total effect of infertility treatment on neonatal mortality was mediated through preterm delivery. In a sensitivity analysis, following corrections for exposure misclassification and unmeasured confounding biases, these risks were higher for early, but not for late, neonatal mortality. CONCLUSION(S) Pregnancies conceived with infertility treatment are associated with increased neonatal mortality, and this association is largely mediated through preterm delivery. However, given the substantial underreporting of infertility treatment, these associations must be cautiously interpreted.
Collapse
Affiliation(s)
- Gordon J Farley
- Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Mark V Sauer
- Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Justin S Brandt
- Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Cande V Ananth
- Division of Epidemiology and Biostatistics, Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey; Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, New Jersey; Cardiovascular Institute of New Jersey and Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey; Environmental and Occupational Health Sciences Institute (EOHSI), Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey.
| |
Collapse
|
3
|
|
4
|
Messini CI, Daponte A, Anifandis G, Mahmood T, Messinis IE. Standards of Care in infertility in Europe. Eur J Obstet Gynecol Reprod Biol 2016; 207:S0301-2115(16)30951-4. [PMID: 28029396 DOI: 10.1016/j.ejogrb.2016.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 10/14/2016] [Indexed: 11/25/2022]
Abstract
Evidence-based medicine is the principal approach to medical practice. There are several debatable issues in infertility, which require clarification. Over the past 20 years, reliable methodology has been developed for the management of infertile couples. This includes high quality diagnostic and therapeutic procedures, which are applied in highly specialised infertility centres. The European Board and College of Obstetrics and Gynaecology (EBCOG) has published Standards of Care for Women's Health in Europe, which should be the cornerstone for the clinicians and service providers in the European Union to establish common protocols within their centres. Each infertility treatment should result in the highest possible success rate and all appropriate measures for the patient's safety should be in place. The treatment protocols should minimise risk of complications, such as ovarian hyperstimulation syndrome (OHSS). The current use of GnRH agonists to trigger final follicle maturation has provided the means for avoiding this syndrome. Additionally, multiple pregnancy rates are still high in assisted reproductive technology (ART). These rates should be reduced by the adoption of single embryo transfer during IVF treatment and by the proper monitoring of ovulation induction protocols. EBCOG Standards of Care for infertility and assisted conception treatment derived from the best available evidence should underpin the provision of high quality infertility services in European countries.
Collapse
Affiliation(s)
- Christina I Messini
- Department of Obstetrics & Gynaecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Alexandros Daponte
- Department of Obstetrics & Gynaecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - George Anifandis
- Department of Obstetrics & Gynaecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Tahir Mahmood
- Department of Obstetrics & Gynaecology, Victoria Hospital, Kirkcaldy, Scotland, UK; European Board and College of Obstetrics & Gynaecology (EBCOG), UK
| | - Ioannis E Messinis
- Department of Obstetrics & Gynaecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece; European Board and College of Obstetrics & Gynaecology (EBCOG), UK.
| |
Collapse
|
5
|
Sobek A, Prochazka M, Klaskova E, Lubusky M, Pilka R. High incidence of monozygotic twinning in infertility treatment. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2016; 160:358-62. [DOI: 10.5507/bp.2016.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/15/2016] [Indexed: 11/23/2022] Open
|
6
|
Monochorionic quadramniotic and triamniotic pregnancies following single embryo transfers: two case reports and a review of the literature. J Assist Reprod Genet 2015; 33:27-32. [PMID: 26564016 PMCID: PMC4717140 DOI: 10.1007/s10815-015-0611-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/28/2015] [Indexed: 11/10/2022] Open
Abstract
Purpose The purpose of this study is to report two cases of monozygotic quadruplet and triplet pregnancies following single embryo transfer (ET). Methods A 29-year-old woman and a 34-year-old woman underwent ART treatment in two affiliated University based ART units. The first woman underwent ICSI with day 3 embryo biopsy for pre-implantation genetic diagnosis (PGD) followed by day 4 transfer, which resulted in a monochorionic quadramniotic (MCQA) quadruplet pregnancy. The second woman underwent conventional IVF with transfer of a single blastocyst, which resulted in a monochorionic triamniotic (MCTA) triplet pregnancy. Results The first patient underwent successful selective foetal reduction at 16 + 3 and 17 + 4 weeks of gestation. Two healthy twin girls were delivered by elective caesarean section at 35 + 6 weeks of gestation. The second patient underwent successful selective foetal reduction at 14 + 1 weeks of gestation. The remaining monochorionic diamniotic (MCDA) twins are well at the time of writing this article. Conclusions To our knowledge, these cases represent the first case of viable MCQA pregnancy following single ET in the world and the third case of a viable MCTA pregnancy following conventional IVF with single ET. Several factors including blastocyst stage transfer and zona pellucida manipulation have been thought to contribute to monozygotic twinning in the context of ART. These two cases add to the growing literature of monozygotic multiple pregnancies following ART.
Collapse
|
7
|
Association between ovarian stimulators with or without intrauterine insemination, and assisted reproductive technologies on multiple births. Am J Obstet Gynecol 2015; 213:511.e1-511.e14. [PMID: 26079626 DOI: 10.1016/j.ajog.2015.06.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 05/10/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022]
Abstract
OBJECTIVE We sought to quantify the risk of multiple births associated with the use of different modalities of medically assisted reproduction. STUDY DESIGN We conducted a case-control study using a birth cohort from 2006 through 2009. This cohort was built with the linkage of data obtained by a self-administered questionnaire and medical, hospital, pharmaceutical, birth, and death databases in Quebec. Cases were pregnancies resulting in multiple live births (International Classification of Diseases, Ninth Revision/International Statistical Classification of Diseases, 10th Revision codes). Each case was matched, on maternal age and year of delivery, with 3 singleton pregnancies (controls) randomly selected among all Quebec singleton pregnancies. Data on the use of different fertility treatments were collected by a self-administered questionnaire. Multiple logistic regression models, adjusted for body mass index, number of previous live births, ethnicity, family income, place of residence, marital status, subfertility, reduction of embryos, diabetes, metformin treatment, folic acid supplementation, and lifestyle factors, were used to calculate the odds ratios (ORs) and confidence intervals (CIs). We evaluated the associations between each type of fertility treatment (ovarian stimulators used alone, intrauterine insemination [IUI] used with ovarian stimulation, and assisted reproductive technologies [ART]) and the risk of multiple births. RESULTS A total of 1407 cases of multiple births and 3580 controls were analyzed. More than half of multiple births following medically assisted reproduction (53.6%) occurred among women having used ovarian stimulation with or without IUI. The use of ovarian stimulators alone and IUI with ovarian stimulation increase the risk of multiple births (adjusted OR, 4.5; 95% CI, 3.2-6.4; and adjusted OR, 9.32; 95% CI, 5.60-15.50, respectively) compared to spontaneous conception. The use of invasive ART was associated with a greatly increased risk of multiple births. Among only the 465 women who used medically assisted reproduction for conception, the use of IUI with ovarian stimulation was associated with an increased risk of multiple births (adjusted OR, 1.98; 95% CI, 1.12-3.49) when compared to ovarian stimulators used alone. Invasive ART were associated with an increased risk of multiple births (adjusted OR, 6.81; 95% CI, 3.72-12.49) when compared to ovarian stimulators used alone. CONCLUSION Although the risk of multiple births associated with invasive ART can be decreased by elective implementing of single embryo transfer, special attention should be paid to the greatly increased risk associated with ovarian stimulation used alone or with IUI.
Collapse
|
8
|
Wirén S, Drevin L, Akre O, Robinson D, Stattin P. Fathering of dizygotic twins and risk of prostate cancer: nationwide, population-based case-control study. PLoS One 2014; 9:e110506. [PMID: 25337702 PMCID: PMC4206421 DOI: 10.1371/journal.pone.0110506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/14/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND An association between male fertility and risk of prostate cancer has been suggested, possibly through lower androgen levels in subfertile men. We evaluated male fertility in relation to risk of prostate cancer by assessing the frequency of fathering of dizygotic twins, a marker of high fertility, among cases of prostate cancer and controls. METHODS We performed a case-control study in Prostate Cancer data Base Sweden (PCBaSe), a nationwide, population-based cohort. PCBaSe was linked to the Swedish twin register for information on zygosity for same-sex twins and to other nationwide health care registers and demographic databases for information on socioeconomic factors, comorbidity, and tumor characteristics for 96 301 prostate cancer cases and 378 583 matched controls. To account for the influence of in vitro fertilization on dizygotic twinning, analyses were restricted to men who had fathered children before 1991, when in vitro fertilization was still uncommon in Sweden. RESULTS 1 112 cases and 4 538 controls had fathered dizygotic twins. Men with dizygotic twins had no increased risk of prostate cancer compared to fathers of singletons; neither for total prostate cancer odds ratio (OR) 0.95(95% CI 0.89-1.02), nor for any risk category, OR 0.97 (95% CI 0.84-1.12) for low-risk disease, and OR 1.04 (95% CI 0.90-1.22) for metastatic disease. CONCLUSION The lack of association between fathering of dizygotic twins and prostate cancer risk give no support for an association between male fertility and prostate cancer risk.
Collapse
Affiliation(s)
- Sara Wirén
- Department of Surgery and Perioperative Sciences, Urology and Andrology, Umeå University, Umeå, Sweden
| | - Linda Drevin
- Regional Cancer Centre, Uppsala University Hospital, Uppsala, Sweden
| | - Olof Akre
- Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - David Robinson
- Department of Urology, Ryhov County Hospital, Jönköping, Sweden
| | - Pär Stattin
- Department of Surgery and Perioperative Sciences, Urology and Andrology, Umeå University, Umeå, Sweden
| |
Collapse
|
9
|
Abstract
Fertility is a couple concept that has been measured since the beginning of demography, and male fecundity (his biological capacity to reproduce) is a component of the fertility rate. Unfortunately, we have no way of measuring the male component directly, although several indirect markers can be used. Population registers can be used to monitor the proportion of childless couples, couples who receive donor semen, trends in dizygotic twinning, and infertility diagnoses. Studies using time-to-pregnancy (TTP) may identify couple subfecundity, and TTP data will correlate with sperm quality and quantity as well as sexual activity and a number of other conditions. Having exposure data available for couples with a fecund female partner would make TTP studies of interest in identifying exposures that may affect male fecundity. Biological indicators such as sperm quality and quantity isolate the male component of fertility, and semen data therefore remain an important source of information for research. Unfortunately, often over half of those invited to provide a sperm sample will refuse, and the study is then subject to a selection that may introduce bias. Because the most important time windows for exposures that impair semen production could be early fetal life, puberty, and the time of ejaculation; longitudinal data over decades of time are required. The ongoing monitoring of semen quality and quantity should continue, and surveys monitoring fertility and waiting TTP should also be designed.
Collapse
|
10
|
Rickard IJ, Courtiol A, Lummaa V. Why is lifetime fertility higher in twinning women? Proc Biol Sci 2012; 279:2510-1; discussion 2512-4. [PMID: 22496189 DOI: 10.1098/rspb.2012.0191] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Ian J Rickard
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
| | | | | |
Collapse
|
11
|
Derom C, Gielen M, Peeters H, Frijns JP, Zeegers MPA. Time trends in the natural dizygotic twinning rate. Hum Reprod 2011; 26:2247-52. [DOI: 10.1093/humrep/der180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
12
|
Abstract
OBJECTIVE Increasing use of infertility treatment and a decline in demographic fertility in some countries have raised concern whether human fecundity is declining or has declined over time. A dramatic decline in semen quality over the past half-century has been proposed and widely discussed, but none of the existing studies provide data good enough for coming to any firm conclusion. RESULTS Results from 19 articles published during the last 5 years on semen quality and fecundity, covering data from the Nordic countries since the year 2000, do not indicate an ongoing decline in fertility. CONCLUSION We will probably never know, whether semen quality and fecundity has declined over time, but we may be able to monitor biological fecundity and semen quality over time from now on. There are both research initiatives and interest from official channels that could provide more funding for infertility research.
Collapse
Affiliation(s)
- Jørn Olsen
- Department of Epidemiology, Institute of Public Health, University of Aarhus, Aarhus, Denmark
| | | | | |
Collapse
|
13
|
Sharara FI, Abdo G. Incidence of monozygotic twins in blastocyst and cleavage stage assisted reproductive technology cycles. Fertil Steril 2010; 93:642-5. [DOI: 10.1016/j.fertnstert.2008.12.130] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 11/27/2008] [Accepted: 12/22/2008] [Indexed: 11/24/2022]
|
14
|
Effects of age on meiosis in budding yeast. Dev Cell 2009; 16:844-55. [PMID: 19531355 DOI: 10.1016/j.devcel.2009.05.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 04/02/2009] [Accepted: 05/05/2009] [Indexed: 11/23/2022]
Abstract
In humans, the frequency with which meiotic chromosome mis-segregation occurs increases with age. Whether age-dependent meiotic defects occur in other organisms is unknown. Here, we examine the effects of replicative aging on meiosis in budding yeast. We find that aged mother cells show a decreased ability to initiate the meiotic program and fail to express the meiotic inducer IME1. The few aged mother cells that do enter meiosis complete this developmental program but exhibit defects in meiotic chromosome segregation and spore formation. Furthermore, we find that mutations that extend replicative life span also extend the sexual reproductive life span. Our results indicate that in budding yeast, the ability to initiate and complete the meiotic program as well as the fidelity of meiotic chromosome segregation decrease with cellular age and are controlled by the same pathways that govern aging of asexually reproducing yeast cells.
Collapse
|
15
|
The variations of human sex ratio at birth during and after wars, and their potential explanations. J Theor Biol 2009; 257:116-23. [DOI: 10.1016/j.jtbi.2008.09.028] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/14/2008] [Accepted: 09/23/2008] [Indexed: 11/19/2022]
|
16
|
Aston KI, Peterson CM, Carrell DT. Monozygotic twinning associated with assisted reproductive technologies: a review. Reproduction 2008; 136:377-86. [DOI: 10.1530/rep-08-0206] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Twin birth rates have increased markedly in developed countries since the 1970s for two primary reasons: increasing maternal age and the advent and increasing use of fertility treatments. In addition, monozygotic (MZ) twin pregnancies have been reported to occur at a significantly higher rate following assisted reproductive technologies (ART) procedures compared with the natural incidence. Twin pregnancies are of concern due to a dramatically increased risk of associated complications. Monozygotic twin pregnancies carry a 10–20% risk of twin–twin transfusion syndrome, and monoamniotic monochorionic twins are additionally at risk for cord entanglement. While the mechanisms and contributory factors for dizygotic twinning are well established, very little is known about the mechanisms involved in MZ twinning or the factors that contribute to its occurrence. In this review, we will discuss a number of potential mechanisms involved in MZ twinning and explore factors that may be contributing to the increased incidence of ART-associated MZ twins. An improved understanding of the factors that contribute to increased MZ twinning associated with ART will help to elucidate the poorly understood mechanisms involved in the process and will further aid in reducing the overall incidence of multiple pregnancies with their associated risks following ART procedures.
Collapse
|
17
|
Feinberg EC, Levens ED, DeCherney AH. Reply of the Authors: Tubal reanastomosis or IVF? Fertil Steril 2008. [DOI: 10.1016/j.fertnstert.2008.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
Zhu JL, Obel C, Hammer Bech B, Olsen J, Basso O. Infertility, infertility treatment, and fetal growth restriction. Obstet Gynecol 2008; 110:1326-34. [PMID: 18055728 DOI: 10.1097/01.aog.0000290330.80256.97] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To examine the association between infertility, with or without treatment, and fetal growth, as well as perinatal and infant mortality. METHODS From the Danish National Birth Cohort (1997-2003), we identified 51,041 singletons born of fertile couples (time to pregnancy 12 months or less), 5,787 born of infertile couples conceiving naturally (time to pregnancy more than 12 months), and 4,317 born after treatment. We defined small for gestational age (SGA) as the lowest 5% of birth weight by sex and gestational age. RESULTS Crude estimates suggested an increased risk of perinatal mortality and SGA among infertile couples (treated and untreated), but the odds ratios (ORs) of perinatal mortality among infertile couples were attenuated after adjustment for maternal age and body mass index (1.32, 95% confidence interval [CI] 0.95-1.84 among untreated and 1.26, 95% CI 0.86-1.85 among treated couples). The elevated risk of SGA among infertile couples persisted after adjustment for maternal age, parity, and smoking (OR 1.24, 95% CI 1.10-1.40 among untreated, and OR 1.40, 95% CI 1.23-1.60 among treated). The risk of SGA increased with time to pregnancy, and a longer time to pregnancy was associated with a small reduction in birth weight across the whole distribution. CONCLUSION The increased risk of SGA observed among infertile couples with or without infertility treatment suggests that infertility may be a risk factor for intrauterine growth restriction. Treatment per se may have little effect on fetal growth. A small-to-moderate increased risk of perinatal mortality in infertile couples cannot be ruled out due to the small number of cases. LEVEL OF EVIDENCE II.
Collapse
Affiliation(s)
- Jin Liang Zhu
- Department of Epidemiology, Institute of Public Health, University of Aarhus, Aarhus C, Denmark.
| | | | | | | | | |
Collapse
|