Table 1.

Characteristics of BCPPs and the comparison group

Characteristics	Comparison group		BCPP group		p value
	n	%	n	%
Total	914		249
Age at breast cancer diagnosis, mean (SD), years	32.26	(4.2)	31.04	(4.2)	<.01
Years of follow‐up, mean (SD)	3.81	(2.6)	4.28	(2.6)	.01
No. of deaths	69		12	4.82
Age at death, mean (SD), years	36.47	(5.1)	35.93	(4.5)	.81
Years between diagnosis and pregnancy, mean (SD)			3.31 (2.1)
Year of breast cancer diagnosis
2002–2004	154	16.9	66	26.5	.01
2005–2007	336	36.8	78	31.3
2008–2010	322	35.2	84	33.7
2011–2014	102	11.2	21	8.4
Stage
I	438	47.9	126	50.6	.75
II	439	48.0	113	45.4
III	37	4.1	10	4.0
Tumor size, cm
≤2	505	55.3	150	60.2	.46
2–5	354	38.7	87	34.9
>5	40	4.4	10	4.0
No information	15	1.6	2	0.8
Positive nodes
0	657	71.9	173	69.5	.13
1‐3	146	16.0	34	13.7
4‐9	40	4.4	15	6.0
≥10	25	2.7	5	2.0
No information	46	5.0	22	8.8
Histological grade
Well differentiated	146	16.0	40	16.1	.27
Moderately differentiated	340	37.2	97	39.0
Poorly or undifferentiated	325	35.6	75	30.1
No information	103	11.3	37	14.9
Hormone receptor status
ER status
ER−	143	31.5	46	34.6	.50
ER+	311	68.5	87	65.4
No information	460		116
PR status
PR−	181	39.9	50	37.6	.64
PR+	273	60.1	83	62.4
No information	460		116
HER2 status
HER2−	71	74.0	17	81.0	.50
HER2+	25	26.0	4	19.0
No information	818		228
Treatmenta
Surgery
None	20	2.2	19	7.6	<.01
Breast conserving	512	56.0	148	59.4
Mastectomy	379	41.5	81	32.5
Radiotherapy	394	43.1	120	48.2	.43
Chemotherapy	670	73.3	148	59.4	<.01
Hormone therapy	535	58.5	111	44.6	<.01

^aTreatment status during the first year of the diagnosis.

Abbreviations: BCPP, patients with breast cancer with a pregnancy after cancer diagnosis; ER, estrogen receptor; HER2, human epidermal growth receptor 2; PR, progesterone receptor.