12.3Ovulation induction in in vitro fertilisation: natural cycles and stimulated cycles

StudyPopulationInterventionOutcomesResultsCommentsStudy typeEL
MacDougall et al. 199483730 women for IVFClomifene citrate-stimulated cycle (n = 16) versus no treatment (n = 14)Clinical pregnancy rate/ET

Multiple pregnancy rate

No. of embryos transferred

Cycle cancellation (due to premature LH surge and poor follicular growth)
Non-significant difference:

Clinical pregnancy rate/ET:
Clomifene: 2/11 (18%)
Natural: 0/4 (0%)

Multiple pregnancy rate: 2 singletons in clomifene group

No. of embryos transferred:
Clomifene: 11/16 (69%)
Natural: 4/14 (28.6%)
RR 2.41 (CI 0.99 to 5.87)

Significant difference:
Cycle cancellation:
Clomifene: 0
Natural: 10
Randomisation using computer-selected numbersRCTIb
Ingerslev et al. 2001838132 couples for IVFClomifene citrate cycle (n = 68; 111 cycles) versus natural cycle (n = 64, 114 cycles)Implantation rate/ET

Clinical pregnancy rate/cycle

Clinical pregnancy rate/transfer

Adverse effects (nausea, hot flushes, mammary tenderness, visual disturbances)
Non-significant difference:

Implantation rate/ET:
Clomifene: 22/85 (26%)
Natural: 4/29 (14%)
RR 1.88 (CI 0.71 to 4.99)

Significant difference:
Clinical pregnancy rate/cycle:
Clomifene: 20/111 (18%)
Natural: 4/114 (3.5%)
RR 5.14 (CI 1.81 to 14.55)

Clinical pregnancy rate/transfer:
Clomifene: 20/59 (34%)
Natural: 4/29 (14%)
RR 2.46 (CI 0.92 to 6.53)

Adverse effects:
CC: 51/111 (46%)
Natural: 2/114 (1.7%)
RR 26.19 (CI 6.53 to 104.98)
Block randomisation by sealed envelopeRCTIb
Levy et al. 199183929 women for IVF-EThMG cycle (n = 13, 26 cycles) versus natural cycle (n = 16, 22 cycles)Clinical pregnancy rate/cycle

Cancellation rate

No. of embryos transferred

Multiple pregnancy rate

Adverse effects
Significant difference:

Clinical pregnancy rate/cycle:
hMG cycle: 6/26 (23%)
Natural cycle: 0/22 (0%)

Cancellation rate ‘higher’ in natural cycle (no data)

No. of embryos transferred:
hMG cycle: 23/26 (88%)
Natural cycle: 11/22(50%)
RR 1.14 (CI 1.77 to 2.75)
Multiple pregnancy rate: no data

Adverse effects: no data
Method of randomisation unclear

Cycles monitored with ultrasound and E2

Ultrasound guided transvaginal follicles aspiration

Crossover study

From: Evidence tables

Cover of Fertility
Fertility: Assessment and Treatment for People with Fertility Problems.
NICE Clinical Guidelines, No. 11.
National Collaborating Centre for Women's and Children's Health (UK).
London (UK): RCOG Press; 2004 Feb.
Copyright © 2004, National Collaborating Centre for Women’s and Children’s Health.

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