Comparison of outcome of pregnancy after intra-uterine insemination (IUI) and IVF

Proteome Mapping of Cervical Mucus and Its Potential as a Source of Biomarkers in Female Tract Disorders

Cervical mucus (CM) is a viscous fluid that is produced by the cervical glands and functions as a uterine cervix plug. Its viscosity decreases during ovulation, providing a window for non-invasive sampling. This study focuses on proteomic characterization of CM to evaluate its potential as a non-invasively acquired source of biomarkers and in understanding of molecular (patho)physiology of the female genital tract. The first objective of this work was to optimize experimental workflow for CM processing and the second was to assess differences in the proteomic composition of CM during natural ovulatory cycles obtained from intrauterine insemination (IUI) cycles and in vitro fertilization (IVF) cycles with controlled ovarian hyperstimulation. Proteomic analysis of CM samples revealed 4370 proteins involved in processes including neutrophil degranulation, cellular stress responses, and hemostasis. Differential expression analysis revealed 199 proteins enriched in IUI samples and 422 enriched in IVF. The proteins enriched in IUI were involved in phosphatidic acid synthesis, responses to external stimulus, and neutrophil degranulation, while those enriched in IVF samples were linked to neutrophil degranulation, formation of a cornified envelope and hemostasis. Subsequent analyses clarified the protein composition of the CM and how it is altered by hormonal stimulation of the uterus.

Effectiveness and safety of intrauterine insemination vs. assisted reproductive technology: emulating a target trial using an observational database of administrative claims

OBJECTIVE

To compare the effectiveness and safety of 1 cycle of assisted reproductive technology (ART) vs. 3 cycles of intrauterine insemination (IUI).

DESIGN

Target trial emulation using observational data.

SETTING

A healthcare claims database (2011-2015).

PATIENT(S)

The patients were 29,021 women aged 18-45 years with an infertility diagnosis and no history of IUI or ART within the past 12 months.

INTERVENTION(S)

One ART cycle immediately, with no more cycles of ART or IUI within the next 4 months; or 1 IUI cycle immediately, with 2 additional consecutive cycles of IUI within the next 4 months unless pregnancy occurred.

MAIN OUTCOME MEASURE(S)

Live births, multiple births, congenital malformations, preterm births, small-for-gestational-age newborns, large-for-gestational-age newborns, admission to neonatal intensive care unit (NICU), gestational diabetes, preeclampsia, and gestational hypertension.

RESULT(S)

The probability of live birth was 27.3% for ART and 26.3% for IUI. The observational analogue of per-protocol risk difference (95% confidence interval) for ART compared with IUI was 1.0% (-0.1%, 2.2%) for live births, 4.3% (3.7%, 4.9%) for multiple births, 3.4% (2.8%, 4.0%) for preterm births, 1.5% (0.9%, 2.1%) for NICU admissions, and 0.6% (0.2%, 1.0%) for gestational diabetes. The risk differences for the other outcomes were <0.5%. The results of the 2 strategies were similar in women ≤40 years, but in women >40 years the probability of live birth was greater for ART (14.4%) than for IUI (7.4%).

CONCLUSION(S)

Compared with 3 cycles of IUI, 1 cycle of ART was estimated to have a similar probability of live birth but slightly higher risks of multiple gestations, preterm births, and NICU admissions.

IUI: review and systematic assessment of the evidence that supports global recommendations

BACKGROUND

IUI with or without ovarian stimulation (OS) has become a first-line treatment option for many infertile couples, worldwide. The appropriate treatment modality for couples and their clinical management through IUI or IUI/OS cycles must consider maternal and perinatal outcomes, most notably the clinical complication of higher-order multiple pregnancies associated with IUI-OS. With a current global emphasis to continue to decrease maternal and perinatal mortality and morbidity, the World Health Organization (WHO) had established a multi-year project to review the evidence for the establishment of normative guidance for the implementation of IUI as a treatment to address fertility problems, and to consider its cost-effectiveness for lower resource settings.

OBJECTIVE AND RATIONALE

The objective of this review is to provide a review of the evidence of 13 prioritized questions that cover IUI with and without OS. We provide summary recommendations for the development of global, evidence-based guidelines based upon methodology established by the WHO.

SEARCH METHODS

We performed a comprehensive search using question-specific relevant search terms in May 2015. For each PICO (Population, Intervention, Comparison and Outcomes) drafted by WHO, specific search terms were used to find the available evidence in MEDLINE (1950 to May 2015) and The Cochrane Library (until May 2015). After presentation to an expert panel, a further hand search of references in relevant reviews was performed up to January 2017. Articles that were found to be relevant were read and analysed by two investigators and critically appraised using the Cochrane Collaboration's tool for assessing risk of bias, and AMSTAR in case of systematic reviews. The quality of the evidence was assessed using the GRADE system. An independent expert review process of our analysis was conducted in November 2016.

OUTCOMES

This review provides an assessment and synthesis of the evidence that covers 13 clinical questions including the indications for the use of IUI versus expectant management, the sperm parameters required, the best and optimal method of timing and number of inseminations per cycle, prevention strategies to decrease multiple gestational pregnancies, and the cost-effectiveness of IUI versus IVF. We provide an evidence-based formulation of 20 recommendations, as well as two best practice points that address the integration of methods for the prevention of infection in the IUI laboratory. The quality of the evidence ranges from very low to high, with evidence that may be decades old but of high quality, however, we further discuss where critical research gaps in the evidence remain.

WIDER IMPLICATIONS

This review presents an evidence synthesis assessment and includes recommendations that will assist health care providers worldwide with their decision-making when considering IUI treatments, with or without OS, for their patients presenting with fertility problems.

Obstetric and perinatal outcomes in subfertile patients who conceived following low technology interventions for fertility enhancement: a comprehensive review

PURPOSE

Low technology interventions for fertility enhancement (LTIFE) are strategies that avoid retrieval, handling, and manipulation of female gametes. The definition of LTIFE is yet to be widely accepted and clarified, but they are commonly used in milder cases of infertility and subfertility. Based on these considerations, the aim of the present study was comprehensively to review and investigate the obstetric and perinatal outcomes in subfertile patients who underwent LTIFE.

METHODS

A literature search up to May 2017 was performed in IBSS, SocINDEX, Institute for Scientific Information, PubMed, Web of Science, and Google Scholar. An evidence-based hierarchy was used according to The Oxford Centre for Evidence-Based Medicine to determine which articles to include and analyze, and to provide a level of evidence of each association between intervention and outcome.

RESULTS

This analysis identified preliminary and low-grade evidence on the influence of LTIFE on obstetric and perinatal outcomes in subfertile women.

CONCLUSIONS

LTIFE women should deserve major consideration from Clinicians/Researchers of Reproductive Medicine, because these treatments could be potentially responsible for mothers' and babies' complications. So far, the lack of well-designed and unbiased studies makes further conclusions difficult to be drawn.

Cyanotic congenital heart disease following fertility treatments in the United States from 2011 to 2014

Objective

To examine the risk for cyanotic congenital heart diseases (CCHDs) among live births in the USA, resulting from various forms of infertility treatments.

Methods

This study is a cross-sectional analysis of live births in the USA from 2011 to 2014. Infertility treatments are categorised into two of the following groups on birth certificates: assisted reproductive technology (ART) fertility treatment (surgical egg removal; eg, in vitro fertilisation and gamete intrafallopian transfer) and non-ART fertility treatment (eg, medical treatment and intrauterine insemination). We compared the risk for CCHD in ART and non-ART fertility treatment groups with those infants whose mothers received no documented fertility treatment and were naturally conceived (NC).

Results

Among 14 242 267 live births from 2011 to 2014, a total of 101 494 live births were in the ART and 81 242 resulted from non-ART fertility treatments. CCHD prevalence in ART, non-ART and NC groups were 393/100 892 (0.39%), 210/80 884 (0.26%) and 10 749/14 020 749 (0.08%), respectively. As compared with naturally conceiving infants, risk for CCHD was significantly higher among infants born in ART (adjusted relative risk (aRR) 2.4, 95% CI 2.1 to 2.7) and non-ART fertility treatment groups (aRR 1.9, 95% CI 1.6 to 2.2). Absolute risk increase in CCHD due to ART and non-ART treatments were 0.03% and 0.02%, respectively. A similar pattern was observed when the analysis was restricted to twins, newborns with birth weights under 1500 g and gestational age of less than 32 weeks.

Conclusions

Our findings suggest an increased risk for CCHD in infants conceived after all types of infertility treatment.

Is primiparity a risk factor for advanced maternal age pregnancies?

OBJECTIVE

Currently, more women are delaying childbearing until their 40s.This study compared the pregnancy and maternal features, pregnancy and foetal outcomes between multiparous and primiparous patients. We compared the same factors between assisted reproductive technology (ART) and non-ART primiparous patients because of the high proportion of ART used in the primiparous patients.

METHODS

The study retrospectively examined 1680 patients, 35 years of age and older, between March 2008 and February 2015.

RESULTS

Comparing the features of these two groups, there was an increased incidence of employment and the use of ART in primiparous patients, while birthweight tended to be higher in the multiparous group. There were no significant differences in pregnancy complications other than hypertension disorders, such as pre-eclampsia and HELLP syndrome, which were significantly more frequent in primiparous patients. The rates of foetal growth retardation and perinatal death were significantly higher in primiparous women. Comparison of the data between ART and non-ART primiparous patients indicated that the ART group had a higher initial body mass index and a lower smoking rate. No significant differences in pregnancy complications or foetal outcome were observed between these two groups.

CONCLUSION

Primiparity is associated with increased pregnancy and foetal complications in advanced age pregnancies. However, the use of ART in this age group does not seem to be an additional risk factor.

Reproductive outcomes after assisted conception

The last three decades have witnessed a dramatic increase in the use of assisted reproductive technology (ART) so that now, in developed countries, 1.7% to 4.0% of all children are born after ART. Although absolute risks appear small, data from prospective and retrospective studies indicate increased risks of adverse maternal and perinatal outcomes after ART as compared with spontaneous conception. Recent studies suggest that underlying maternal factors and subfertility play an important role in some of these outcomes rather than the ART procedure itself. A significant risk of assisted conception is multiple pregnancies, but even singleton pregnancies achieved by ART are at a higher risk of hypertensive disease, diabetes, prematurity, low birth weight, and perinatal mortality even after adjusting for confounders. Couples undergoing ART procedures should be counseled in advance regarding increased risks of pregnancy complications and higher rates of obstetric interventions. Although conflicting data exist, studies of children born from ART suggest increased rates of congenital malformations, imprinting disorders (Beckwith-Wiedemann syndrome and Angelman syndrome), and marginally increased risk of cancer. However, the current evidence is inadequate, and prospective long-term studies are needed to eliminate the effect of confounders and draw definite conclusions about the long-term outcomes after ART. The absolute risk of imprinting disorders remains small, and routine screening is not recommended at present. The long-term outcomes after ART are difficult to evaluate because of the variability in ART methods and data reporting, and there is a need for standardized methodology for follow-up after ART.

Why do singletons conceived after assisted reproduction technology have adverse perinatal outcome? Systematic review and meta-analysis

BACKGROUND

Assisted reproduction technology (ART) is used worldwide, at increasing rates, and data show that some adverse outcomes occur more frequently than following spontaneous conception (SC). Possible explanatory factors for the well-known adverse perinatal outcome in ART singletons were evaluated.

METHODS

PubMed and Cochrane databases from 1982 to 2012 were searched. Studies using donor or frozen oocytes were excluded, as well as those with no control group or including <100 children. The main outcome measure was preterm birth (PTB defined as delivery <37 weeks of gestation), and a random effects model was used for meta-analyses of PTB. Other outcomes were very PTB, low-birthweight (LBW), very LBW, small for gestational age and perinatal mortality.

RESULTS

The search returned 1255 articles and 65 of these met the inclusion criteria. The following were identified as predictors for PTB in singletons: SC in couples with time to pregnancy (TTP) > 1 year versus SC singletons in couples with TTP ≤ 1 year [adjusted odds ratio (AOR) 1.35, 95% confidence interval (CI) 1.22, 1.50]; IVF/ICSI versus SC singletons from subfertile couples (TTP > 1 year; AOR 1.55, 95% CI 1.30, 1.85); conception after ovulation induction and/or intrauterine insemination versus SC singletons where TTP ≤ 1 year (AOR 1.45, 95% CI 1.21, 1.74); IVF/ICSI singletons versus their non-ART singleton siblings (AOR 1.27, 95% CI 1.08, 1.49). The risk of PTB in singletons with a 'vanishing co-twin' versus from a single gestation was AOR of 1.73 (95% CI 1.54, 1.94) in the narrative data. ICSI versus IVF (AOR 0.80, 95% CI 0.69-0.93), and frozen embryo transfer versus fresh embryo transfer (AOR 0.85, 95% CI 0.76, 0.94) were associated with a lower risk of PTB.

CONCLUSIONS

Subfertility is a major risk factor for adverse perinatal outcome in ART singletons, however, even in the same mother an ART singleton has a poorer outcome than the non-ART sibling; hence, factors related to the hormone stimulation and/or IVF methods per se also may play a part. Further research is required into mechanisms of epigenetic modification in human embryos and the effects of cryopreservation on this, whether milder ovarian stimulation regimens can improve embryo quality and endometrial conditions, and whether longer culture times for embryos has a negative influence on the perinatal outcome.

Singleton pregnancy outcomes after assisted and non-assisted reproductive technology in infertile patients

Purpose

Singleton pregnancy after assisted reproductive technology (ART) has been associated with higher risks of adverse pregnancy outcome than naturally conceived singleton pregnancy. This study was to elucidate whether the ART procedure is responsible for abnormal pregnancy outcome comparing those after ART and non-ART in infertile patients.

Methods

We compare the singleton pregnancy outcome of infertile patients in our university hospital between 2000 and 2008 following ART (351 pregnancies) and non-ART (213 pregnancies) procedures. Pregnancy outcome parameters were incidence of pregnancy induced hypertension, placenta previa, placental abruption, cesarean delivery, preterm birth, very preterm birth, stillbirth, low birth weight and very low birth weight.

Results

Most of the pregnancy outcome parameters were not significantly different between the ART group and the non-ART group. Only placenta previa was significantly higher in the ART group than in the non-ART group (odds ratio 4.0; 95 % CI 1.2-13.7).

Conclusions

ART procedure may itself be a risk factor for the development of placenta previa. Some of the abnormal perinatal outcomes that had been previously attributed to ART, however, may be due to the baseline characteristics of infertile patients.

Comparison of the pregnancy outcomes of subfertile women after infertility treatment and in naturally conceived pregnancies

BACKGROUND

Adverse obstetric outcomes in pregnancies achieved through assisted reproductive technology (ART) could either be due to the technology or to the underlying subfertility or to both. To address this issue, we compared the pregnancy outcomes of singletons conceived naturally after a long time to pregnancy (TTP) with those of ART pregnancies.

METHODS

We analysed an existing birth database. Altogether 428 ART pregnancies were compared with 928 spontaneously conceived pregnancies with TTP of 2 years or more, during the period 1989-2007 at Kuopio University Hospital, Finland. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for pregnancy outcomes.

RESULTS

Between treated and untreated subfertile women no significant differences were found in the rates of Caesarean sections (OR 1.21, 95% CI 0.89-1.64), preterm births (OR 1.28, 95% CI 0.81-2.03), small for gestational age (SGA) birthweight (OR 0.95, 95% CI 0.65-1.39), need of neonatal intensive care (OR 1.28, 95% CI 0.88-1.88) or low Apgar scores (OR 1.19, 95% CI 0.47-3.04). However, compared with pregnancies of women with TTP 0-6 months, ART pregnancies had significantly increased risks of preterm or very preterm birth, low birthweight and need of neonatal intensive care.

CONCLUSIONS

The risks of preterm birth, SGA, need for neonatal intensive care and low Apgar scores were not significantly different between subfertile women who conceived spontaneously and those who conceived through ART indicating that maternal factors relating to subfertility and not only infertility treatment are associated with adverse pregnancy outcomes.

Genetische Risiken der assistierten Reproduktion

Kinderwunschpatienten müssen vor einer Behandlung über die genetischen Risiken individuell beraten werden. Chromosomenanomalien sind für etwa 5% der männlichen Subfertilität verantwortlich. Im Fall einer Azoospermie liegt die Rate bei 15%. Daher sollte bei einer männlichen Subfertilität bei einer Spermienzahl <20 Mio./ml eine Chromosomenanalyse bei beiden Partnern durchgeführt werden, da ein erhöhtes Risiko für genetische Veränderungen besteht. Ein Klinefelter-Syndrom oder eine Robertson-Translokation können für eine männliche Subfertilität verantwortlich sein. Mutationen des CFTR-Gens sowie Veränderungen des Y-Chromosoms findet man gehäuft bei männlicher Subertiltät. Mikrodeletionen treten am häufigsten am langen Arm des Y-Chromosoms auf (Yq) und betreffen Gene, die direkt in die Spermatogenese involviert sind, insbesondere das AZF-Gen.

Bezüglich Schwangerschaftsverlauf und neonatalem Outcome der Kinder müssen Kinderwunschpatienten darüber aufgeklärt werden, dass während der Schwangerschaft und der Geburt häufiger Komplikationen auftreten als nach Spontankonzeption. Das Fehlgeburtsrisiko ist um das 1,3-Fache erhöht, dies ist jedoch vermutlich Folge der Subfertilität sowie weiterer Risikofaktoren, die die Paare mitbringen, und nicht Folge der Therapie. Das Risiko für Schwangerschaftskomplikationen wie Präeklampsie, Wachstumsretardierung und Totgeburt ist ebenfalls erhöht. Zudem ist das Fehlbildungsrisiko sowohl bei der IVF-Therapie als auch bei der ICSI-Therapie um das 1,3-Fache erhöht.

In vitro fertilization and preterm delivery, low birth weight, and admission to the neonatal intensive care unit: a prospective follow-up study

OBJECTIVE

To compare the risk of preterm delivery, low birth weight, and admission of the newborn to a neonatal intensive care unit (NICU) in women pregnant after fertility treatment and subfertile women with the risk in fertile women.

DESIGN

Prospective follow-up study.

SETTING

Aarhus University Hospital, Skejby, Denmark, 1989-2006.

PATIENT(S)

A total of 20,080 liveborn singletons.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Preterm delivery, low birth weight, and admission of the newborn to a NICU.

RESULT(S)

After adjustment we found a statistically significantly increased risk of preterm delivery and very preterm delivery in women who conceived after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) compared with fertile women. Compared with fertile women, the risk of preterm delivery and very preterm delivery was not statistically significantly different in women pregnant after non-IVF assisted reproductive treatment (non-IVF ART) or subfertile women. We found no association between IVF/ICSI and the risk of low birth weight at term or admittance to the NICU.

CONCLUSION(S)

The increased risk of preterm delivery after IVF/ICSI may be due to the fertility treatment or unknown characteristics in the couples who undergo IVF/ICSI.

Obstetric outcomes in donor oocyte pregnancies compared with advanced maternal age in in vitro fertilization pregnancies

OBJECTIVE

To evaluate obstetric complications in women who conceived through donated oocytes compared with women who conceived through assisted reproduction using autologous oocytes.

DESIGN

Retrospective cohort analysis.

SETTING

Stanford Hospital and Clinics and Lucille Packard Children's hospital, both tertiary referral centers.

PATIENT(S)

A cohort of 71 oocyte recipients who underwent in vitro fertilization (IVF) were compared to all women over 38 years who conceived through IVF with autologous oocytes (n = 108) between January 1, 2001, and December 31, 2005, at Stanford University and subsequently delivered infants at Lucille Packard Children's Hospital.

INTERVENTION(S)

Assisted reproductive technology with donor oocytes.

MAIN OUTCOME MEASURE(S)

Obstetric charts of the donor-oocyte recipients were compared for all women over 38 years old who had conceived through IVF with autologous oocytes at the same center (n = 108) and delivered at the same hospital during the same time period. Perinatal complications including preeclampsia, diabetes, preterm labor, preterm premature rupture of membranes and placental abnormalities, mode of delivery, presentation, Apgar scores, gestational age at delivery, and weight were compared between the groups.

RESULT(S)

Oocyte recipients and autologous oocyte controls had similar rates of complications of prematurity, hypertensive disorders of pregnancy, gestational diabetes, and placental abnormalities. Infant birth weights and gestational age at time of delivery were similar between the two groups.

CONCLUSION(S)

This study suggests that women undergoing IVF with donor oocytes are not at increased risk for complications during pregnancy or at increased immediate neonatal complications compared with women of advanced maternal age undergoing IVF with autologous oocytes.

Outcome of assisted reproduction

In-vitro fertilisation has been done for nearly 30 years; in developed countries at least 1% of births are from assisted reproductive therapies (ART). These children now represent a substantial proportion of the population but little is known about their health. Some of the morbidity associated with ART does not result from the techniques but from the underlying health risks of being subfertile. Much of the amplified risk associated with ART is related to high birth order. However, risk of intrauterine and subsequent perinatal complications is enhanced after ART, and urogenital malformations can be present in boys, even in singleton infants. No increase in discord or other difficulties within families has been recorded. Long-term follow-up of children born after ART to reproductive age and beyond is necessary.

Birthweight of singletons after assisted reproduction is higher after single- than after double-embryo transfer

BACKGROUND

Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET).

METHODS

We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child.

RESULTS

Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 +/-617.5 g versus 3324.6+/-509.7 g , P<0.01). Also preterm birth (<37 weeks) [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.06-2.94] and low birthweight (<2500 g) (OR 3.38, 95% CI 1.86-6.12) are significantly more common in DET singletons.

CONCLUSIONS

Singleton birth after SET is advantageous compared with DET. This sheds new light on the reasons why singleton births following ART do worse than spontaneously conceived singletons in IVF programs, where double- or multiple-embryo transfer is standard.

First-trimester bleeding and pregnancy outcome in singletons after assisted reproduction

BACKGROUND

First-trimester bleeding is frequent in assisted reproductive technique (ART) pregnancies. It is unknown whether first-trimester bleeding, if not ending in a spontaneous abortion, negatively influences further pregnancy outcome in ART in singletons.

METHODS

Data were obtained from our ART database (1993-2002), with 1432 singleton ongoing pregnancies being included in this study. The outcome measures-second-trimester and third-trimester bleeding, preterm contraction rates, pregnancy duration, birthweight, Caesarean section rates, intrauterine growth retardation (IUGR), preterm prelabour rupture of membranes (P-PROM), neonatal intensive care unit (NICU) admission and perinatal mortality-were compared in the groups with and without first-trimester bleeding.

RESULTS

Significantly more singleton pregnancies resulted from a vanishing twin in the group with first-trimester bleeding (8.7%) than in the controls (4.0%). A correlation was found between the incidence of first-trimester bleeding and the number of embryos transferred. First-trimester bleeding led to increased second-trimester [odds ratio (OR)=4.56; confidence interval (CI)=2.76-7.56] and third-trimester bleeding rates (OR=2.85; CI=1.42-5.73), P-PROM (OR=2.44; CI=1.38-4.31), preterm contractions (OR=2.27; CI=1.48-3.47) and NICU admissions (OR=1.75; CI=1.21-2.54). First-trimester bleeding increased the risk for preterm birth (OR=1.64; CI=1.05-2.55) and extreme preterm birth (OR=3.05; CI=1.12-8.31).

CONCLUSIONS

First-trimester bleeding in an ongoing singleton pregnancy following ART increases the risk for pregnancy complications. The association between first-trimester bleeding, the number of embryos transferred and adverse pregnancy outcome provides a further argument in favour of single-embryo transfer.

Comparative birth weights of singletons born after assisted reproduction and natural conception in previously infertile women

BACKGROUND

The possible interference of assisted reproduction techniques (ART) with epigenetic reprogramming during early embryo development has recently sparked renewed interest about the reported lower birth weight among infants born as a consequence of infertility treatments. However, the latter finding so far has relied on the comparison of the birth weight of infants conceived with ART to general population data. A more appropriate comparison group should involve pregnancies in infertile women after natural conception. Therefore, we compared neonatal birth weight data of infants born after various ART treatments, including intrauterine insemination (IUI), with those of previously infertile women achieving pregnancy after sexual intercourse.

METHODS

Between August 1996 and March 2004 the data of all infertile women presenting in the infertility unit of the University Women's Hospital of Basel, Switzerland, were collected prospectively, adding up to 995 intact pregnancies and deliveries. The birth weight of all infants resulting from 741 singleton pregnancies were analysed with regard to the patients' characteristics, the occurrence of complications during pregnancy and the type of infertility treatment with which the pregnancies were achieved.

RESULTS

Comparison of duration of pregnancy and birth weight of infants born after infertility treatment confirms a shorter pregnancy span and a lower mean birth weight in infants born after IVF and ICSI. If women with pregnancies after ART deliver before term, neonatal birth weight is significantly lower.

CONCLUSIONS

There is a specific effect of ART, mainly IVF and ICSI, on both shortening the duration of pregnancy and lowering neonatal birth weight. Both these parameters seem to be interrelated consequences of some modification in the gestational process induced by the infertility treatment. Freezing and thawing of oocytes in the pronucleate stage had a lesser impact on pregnancy span and on neonatal birth weight.