Incidence and complications of multiple gestation in Canada: proceedings of an expert meeting

No-271-Delayed Child-Bearing

OBJECTIVE

To provide an overview of delayed child-bearing and to describe the implications for women and health care providers .

OPTIONS

Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome . This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices .

OUTCOMES

Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age . Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section . This guideline provides a framework to address these issues .

EVIDENCE

Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility) . The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements . Data were extracted based on the aims, sample, authors, year, and results .

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.

SPONSOR

The Society of Obstetricians and Gynaecologists of Canada.

RECOMMENDATIONS

Birth weight discordance and adverse perinatal outcomes

OBJECTIVE

Our purpose was to examine the association between discordant growth and perinatal mortality and morbidity among twins with careful adjustment for maternal confounding factors.

STUDY DESIGN

Two cohorts with and without chorionicity data were compared using generalized estimating modeling.

RESULTS

Our population-based dataset consisted of 12,656 individual twins from whom 4% (452/12,656) had≥30% growth discordance. A subgroup of this population with chorionicity information had an incidence of 7.3%≥30% growth discordance. In growth-discordant twins, perinatal mortality and morbidity were higher than concordant pairs (P<0.01). Low Apgar score and perinatal mortality were more frequent in growth-discordant twins compared with growth-concordant ones (all P<0.01).

CONCLUSION

Birth weight discordance (BWD) places twins at increased risk of perinatal mortality. Growth discordance was also an independent risk factor for lower Apgar score of 5 min less than 5.

Endometrial scratching performed in the non-transfer cycle and outcome of assisted reproduction: a randomized controlled trial

OBJECTIVES

To investigate the effect of endometrial scratching, performed during oral contraceptive pill (OCP) pretreatment, on reproductive outcome and on ultrasound markers of endometrial receptivity, and to assess the pain involved in the procedure, in unselected women undergoing assisted reproductive techniques (ART).

METHODS

Women undergoing ART were randomly allocated to undergo either endometrial scratching with a pipelle de Cornier or a sham procedure, 7-14 days before starting controlled ovarian stimulation (COS). We evaluated subsequent rates of clinical pregnancy, live birth, implantation, miscarriage and multiple pregnancy. Pain during the procedure was evaluated using a 10-cm visual analog scale. Endometrial thickness and volume and three-dimensional power Doppler (3D-PD) indices (vascularization index (VI), flow index (FI) and vascularization flow index (VFI)) were assessed during COS when there was at least one follicle ≥ 17 mm in diameter.

RESULTS

We included 158 women. Endometrial scratching was associated with higher rates of live birth (41.8% vs 22.8%, P = 0.01) and clinical pregnancy (49.4% vs 29.1%, P = 0.01) and higher pain score (6.42 ± 2.35 cm vs 1.82 ± 1.52 cm, P < 0.001), endometrial VI (3.71 ± 1.77 vs 2.95 ± 1.56, P < 0.01) and VFI (0.97 ± 0.51 vs 0.76 ± 0.40, P < 0.01). There was no significant effect of endometrial scratching on rate of miscarriage (15.4% vs 21.7%, P = 0.53) or multiple pregnancy (22.5% vs 25.0%, P = 0.79), or on endometrial thickness (10.12 ± 1.55 mm vs 9.98 ± 1.62 mm, P = 0.59), endometrial volume (6.18 ± 1.63 cm(3) vs 6.01 ± 1.48 cm(3) , P = 0.51) or FI (26.12 ± 2.82 vs 25.91 ± 2.72, P = 0.65).

CONCLUSIONS

Endometrial scratching performed once, during OCP pretreatment 7-14 days before starting COS, increases the chance of live birth and clinical pregnancy, but might cause considerable pain.

Relationship of mode of conception and sex concordance with mortality/morbidity in preterm twins

OBJECTIVE

To assess the association of mode of conception and sex concordance with neonatal outcomes in very preterm twins.

STUDY DESIGN

Twin pairs born at gestational age ≤ 32 weeks and admitted to a Level 3 neonatal intensive care unit (NICU) in 2010-2011 were retrospectively identified from the Canadian Neonatal Network™ database. A composite outcome representing neonatal mortality or any severe morbidity (intraventricular hemorrhage grades ≥ 3 or periventricular leukomalacia, retinopathy of prematurity stages ≥ 3, bronchopulmonary dysplasia, or necrotizing enterocolitis stages ≥ 2) was compared between twins conceived using assisted reproduction technologies (ARTs) or spontaneously (SP), and tested for association with sex concordance in individual-level and pair-wise multivariable logistic regression analyses.

RESULTS

Study subjects included 1,508 twins from 216 ART (53 [25%] male-male, 104 [48%] male-female, and 59 [27%] female-female) and 538 SP (192 [36%] male-male, 123 [23%] male-female, and 223 [41%] female-female) pairs. No statistically significant association was detected between mode of conception and the composite outcome of mortality/morbidities. The composite outcome was significantly higher in same-sex than in opposite-sex twins (OR = 1.68; 95% CI = [1.09, 2.59]). This relationship was most pronounced in ART pairs (OR = 2.25; 95% CI = [1.02, 4.98]), with increased rates in one or both twins from male-male versus opposite-sex ART pairs (OR = 3.0; 95% CI = [1.07, 8.36]).

CONCLUSION

Same-sex pairing was associated with higher mortality/morbidities in very preterm twins admitted to the NICU, and can be used in clinical practice to identify twins at higher risk of adverse neonatal outcomes.

Multiple births associated with assisted human reproduction in Canada

OBJECTIVE

Assisted human reproduction has been associated with increased rates of multiple births. Data suggest that twins and higher order multiple pregnancies are at risk for pre- and postnatal health complications that contribute to stress on both the family and the Canadian health care system. No published Canadian data estimate the contribution of assisted human reproduction to multiple birth rates. This study was designed to determine the contributions of age and assisted human reproduction to multiple birth rates in Canada.

METHODS

We performed analyses of existing Canadian databases, using a mathematical model from the Centers for Disease Control and Prevention. More specifically, data from the Canadian Vital Statistics: Births and Stillbirths database were combined with data from the Canadian Assisted Reproductive Technologies Register collected by the Canadian Fertility and Andrology Society. Datasets were standardized to age distributions of mothers in 1978.

RESULTS

RESULTS suggest that in vitro fertilization, ovulation induction, and age each contribute more to the rates of triplets than to twins. As expected, the contribution of natural factors was higher to twins than to triplets.

CONCLUSION

These are the first Canadian data analyzed to separate and measure the contributions of age and assisted reproductive technologies to multiple birth rates. Our findings are important for guiding physician and patient education and informing the development of treatment protocols that will result in lower-risk pregnancies and improved long-term health for women and their offspring.

Effect of older maternal age on birth outcomes in twin pregnancies: a population-based study

OBJECTIVE

We compared perinatal mortality, preterm birth (<37, <33 and <28 weeks), small for gestational age (SGA), Apgar score (<4), mechanical ventilation (1 days) and prolonged neonatal intensive care unit (NICU) hospitalization (13 days) between twins of 25 to 34 and >35-year-old women. Further, we examined whether older maternal age effects were modified by parity or otherwise affected by chorionicity.

STUDY DESIGN

We carried out a population-based retrospective cohort study including all twin births in British Columbia (BC), Canada, from 1999 to 2003. The BC perinatal database registry was used to obtain clinical, behavioral and demographic data. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated using generalized estimating equation models.

RESULT

Overall, twins of older women were more likely to be born preterm (<37 weeks), but not very or extremely preterm (<33 weeks). These twins were not at increased risk of perinatal death, mechanical ventilation or were not SGA compared with twins of younger women. Twins of older primiparous women did not have an elevated risk of NICU hospitalization; twins born to older multiparous women had higher risk (OR=1.8; 95% CI: 1.2 to 2.6). Analyses restricted to opposite-sex (dichorionic) twins showed that perinatal death, mechanical ventilation and very preterm birth occur less likely among older women (OR=0.2 (95% CI: 0.0 to 0.8), OR=0.3 (95% CI: 0.1 to 0.7) and OR=0.4 (95% CI: 0.2 to 0.7), respectively). Further, the risk of late preterm birth was increased and NICU hospitalization was reduced among opposite-sex twins born to older compared with younger primiparous women (OR=1.9 (95% CI: 1.3 to 2.8) and OR=0.2 (95% CI: 0.1 to 0.5), respectively).

CONCLUSION

Twins of older mothers did not have an elevated risk for most adverse birth outcomes, except for late preterm birth. Risks of neonatal care admission may be elevated among older multiparous women.

HP-HMG versus rFSH in treatments combining fresh and frozen IVF cycles: success rates and economic evaluation

The economic implications of the choice of gonadotrophin influence decision making but their cost-effectiveness in frozen-embryo transfer cycles has not been adequately studied. An economic evaluation was performed comparing highly purified human menopausal gonadotrophin (HP-HMG) and recombinant FSH (rFSH) using individual patient data (n=986) from two large randomized controlled trials using a long agonist IVF protocol. The simulation model incorporated live birth data and published UK costs of IVF-related medical resources. After treatment for up-to-three cycles (one fresh and up to two subsequent fresh or frozen cycles conditional on availability of cryopreserved embryos), the cumulative live birth rate was 53.7% (95% CI 49.3-58.1%) for HP-HMG and 44.6% (40.2-49.0%) for rFSH (OR 1.44, 95% CI 1.12-1.85; P<0.005). The mean costs per IVF treatment for HP-HMG and rFSH were pound5393 ( pound5341-5449) and pound6269 ( pound6210-6324), respectively (number needed to treat to fund one additional treatment was seven; P<0.001). With maternal and neonatal costs applied, the median cost per IVF baby delivered with HP-HMG was pound11,157 ( pound11,089-11,129) and pound14,227 ( pound14,183-14,222) with rFSH (P<0.001). The cost saving using HP-HMG remained after varying model parameters in a probabilistic sensitivity analysis.

Assisted reproductive technologies (ART) in Canada: 2006 results from the Canadian ART Register

OBJECTIVE

To present a report on assisted reproductive technologies (ART) cycles performed in 2006 in Canada and show trends in outcomes over time. This is the sixth annual report from the Canadian ART Register (CARTR).

DESIGN

Prospective cohort study.

SETTING

Twenty-five of 25 ART centers in Canada.

PATIENT(S)

Couples undergoing ART treatment in Canada during 2006.

INTERVENTION(S)

ART treatments, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and frozen embryo transfer (FET).

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, live birth, and multiple birth rates.

RESULT(S)

A total of 12,052 ART cycles was reported to CARTR. In 8278 IVF/ICSI cycles using the woman's own oocytes, the clinical pregnancy rate per cycle started was 33.7% (38.6% per ET), and the live birth rate was 27.1%; the multiple birth rate per delivery was 30.3%, with a high-order multiple birth rate of 1.5%. In 64% of cycles, ICSI was performed. One or two embryos were transferred in 67% of cycles. In 350 IVF/ICSI cycles using donor oocytes, the clinical pregnancy rate was 42.3%, and the live birth rate was 33.6%; the multiple birth rate was 37.3%, with no triplet birth. In 2838 FET cycles using the woman's own oocytes, the clinical pregnancy rate was 24.3%, and the live birth rate was 18.6%; the multiple birth rate was 22.5%, with a triplet birth rate of 0.6%. Birth outcomes were unknown for 3.6% of ongoing pregnancies.

CONCLUSION(S)

For 2006, CARTR achieved 100% voluntary participation from Canadian ART centers for the fourth consecutive year. Clinical pregnancy and live birth rates continued to increase in 2006 compared with previous years, but multiple birth rates decreased only slightly.

Assisted reproductive technologies in Canada: 2005 results from the Canadian Assisted Reproductive Technologies Register

OBJECTIVE

To present a report on assisted reproductive technologies (ART) cycles performed in 2005 in Canada. This is the fifth annual report from the Canadian ART Register (CARTR).

DESIGN

Prospective cohort study.

SETTING

Twenty-five of 25 ART centers in Canada.

PARTICIPANT(S)

Couples undergoing ART treatment in Canada during 2005.

INTERVENTION(S)

ART treatments, including IVF, intracytoplasmic sperm injection (ICSI), and frozen ET (FET).

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, live birth, and multiple birth rates.

RESULT(S)

A total of 11,414 ART cycles was reported to CARTR. In 8195 IVF/ICSI cycles using the women's own oocytes, the clinical pregnancy rate per cycle started was 32.1% (37.5% per ET procedure), and the live birth rate was 25.6%; the multiple birth rate per delivery was 30.8%, with a triplet birth rate of 1.4%. IVF was performed in 40% of cycles and ICSI in 60% with similar pregnancy rates. One or two embryos were transferred in 68% of cycles; transferring more embryos did not increase the pregnancy rate. In 301 IVF/ICSI cycles using donor oocytes, the clinical pregnancy rate was 46.5%, and the live birth rate was 35.2%; the multiple birth rate was 33.3%, with no triplet birth. In 2498 FET cycles using the woman's own oocytes, the clinical pregnancy rate was 22.8%, and the live birth rate was 17.4%; the multiple birth rate was 24.5%, with a triplet birth rate of 1.6%. Compared with singletons, babies from multiple births had higher risks for preterm birth, low birth weight, and perinatal death.

CONCLUSION(S)

For 2005, CARTR achieved 100% voluntary participation from Canadian ART centers for the third consecutive year. Clinical pregnancy and live birth rates continued to increase in 2005 compared with previous years.