Table 2.

Association between serum progesterone concentration at embryo transfer and IVF outcomes among 229 fresh egg donor cycles

Outcome	P a < 20 ng/ml (n = 75)	P >= 20 ng/ml (n = 154) (Referent group)	RR (95 % CI)	p-value
Clinical pregnancyb	42 (56.0 %)	113 (73.4 %)	0.75 (0.60–0.94)	0.01
Spontaneous abortionc	4 (5.3 %)	13 (8.4 %)	0.80 (0.27–2.33)	0.68
Live birthd	38 (50.7 %)	100 (64.9 %)	0.77 (0.60–0.98)	0.04
Multiple birthe	14 (18.7 %)	40 (26.0 %)	0.72 (0.42–1.25)	0.24

^aP = progesterone, measured on the day of embryo transfer

^bClinical pregnancy was defined as the presence of at least one intrauterine gestational sac

^cSpontaneous abortion was defined as loss of a clinical pregnancy prior to 24 weeks’ gestational age

^dLive birth was defined as birth of a viable infant after 23 weeks and 6 days’ gestational age

^eMultiple birth was defined as delivery of two or more viable infants