| Sexual intercourse around the time of embryo transfer is not harmful to embryo development. Implantation rate is improved (RR = 1.43) by peri-transfer coitus. |
Citation/s:
Tremellen, KP et al. The effect of intercourse on pregnancy rates during assisted human
reproduction. Hum. Reprod. 2000; 15: 2653-2658
Lead author's name and fax: kelton.tremellen@adelaide.edu.au
Three-part Clinical Question: In IVF/ICSI/FET patients undergoing embryo transfer, does sexual intercourse reduce the chances of pregnancy
Search Terms: Cochrane, Medline, hand searches (Sex, or sexual intercourse or intercourse or coitus) and (IVF or ICSI or GIFT or Assisted conception or Assisted reproductive technology) Each combination searched as either text word or MeSH
The Study:Cohort Study.
The Study Patients: Couples (women aged 18-40 years) undergoing fresh or frozen embryo transfers from three centres in Australia and Spain. Exclusion criteria were: use of donor gametes, Hepatitis B,C or HIV infections in the male partner.
200 FET cycles in one Australian centre; 400 fresh cycles in two Spanish centres.
Exposure of Interest: Sexual intercourse around the time of ET.
302 randomised to have sex, 298 to abstain. (654 and 689 embryos transferred respectively)
The Outcome: Implantation rate (number of gestational sacs at 6 weeks
scan / 100 transferred embryos)
| Study features | Yes | No | Can't tell |
| Subjects defined and similar in other important ways? | X | ||
|---|---|---|---|
| Exposures and outcomes either objective or measured blind? | X | ||
| Follow-up long enough? | X | ||
| Follow-up complete? | X |
The Evidence:
| Implantation rate (number... | |||||
| Present | Absent | ||||
| Number | Proportion | Number | Proportion | ||
| Sexual intercourse around... | Yes | 72 | 0.11 | 582 | 0.89 |
|---|---|---|---|---|---|
| No | 53 | 0.08 | 636 | 0.92 | |
| Relative Risk: | 1.43 | ||||
| Number Needed to Harm: | 30 | 95% CI: (RR) | 1.39 to 1.47 | ||
| Chi Square | 3.99 | ||||
Comments:
This is the first study to show that sex around the time of embryo transfer, far from
being harmful may even be beneficial to embryo development. Most of the patients were
however from Spanish centres (only fresh embryos studied) where an average of 4 embryos
were replaced, whereas in the Australian centre (only thawed embryos studied), regulations
in place ensured only an average embryo replacement of 2. It is hard to say whether this,
and other factors discussed by the authors accounted for the slight difference in
sub-group analyses, which showed no effect of sexual intercourse on implantation rates in
Australian women, but a significant beneficial effect in Spanish women. The pooled results
were therefore used in this appraisal.
This study (with altogether 1,343 embryos transferred) had sufficient power to detect a 50% increase in IMPLANTATION RATE (i.e. from 8% to 12% - RR of 1.5), but not in pregnancy rate as claimed by the authors. In fact, the authors would have required a total of 2700 cycles of treatments reaching embryo transfer to detect an increase in CLINICAL PREGNANCY rate from 21% to 24% (RR of 1.2).
Conclusions: Whereas this study's finding on sexual intercourse and implantation rates are valid, a much larger study will be required to demonstrate the effect of sex on clinical pregnancy rate. Based on the level of this evidence, there is no reason to advise against sexual intercourse by those who feel inclined to it during assisted conception treatments.
Critical appraisal by: Bolarinde Ola MRCOG Clinical Research Fellow, Assisted
Conception Unit, Birmingham Women's Hospital, Birmingham B15 2TG, United Kingdom; 04
February 2001
Email: bolarinde.ola@bham-womens.thenhs.com
Kill or update By: 04 February 2003