Table 8.

Risk factors for lumbopelvic pain during (DP) and after (AP) pregnancy

Factor	x/ya	Evidence	Outcomesb	References	Confounders
Maternal age	11/23	Conflicting	DP: younger	[28, 80, 82, 83]	Parity [59, 76]
			DP: older	[59, 76d]
			DP: no effect	[31, 35,45, 48, 60, 61, 76e, 78, 107]
			AP: younger	[13f, 53, 81, 95, 109]
			AP: no effect	[13g, 17, 96]
Number of pregnancies	11/21	Conflicting	DP: higher	[23, 28, 45, 59, 76d, 82]	–
			DP: no effect	[7, 31, 35, 48, 61, 76e, 78, 80, 107]
			AP: lower	[53, 108]
			AP: higher	[17, 81, 109]
			AP: no effect	[96]
Maternal height	1/8	Weak	DP: no effect	[35, 48, 59, 61, 78, 82, 99]	Maternal weight [13]
			AP: shorter	[13]g
Maternal weight	5/16	Weak	DP: heavier	[23, 28, 45, 78h]	–
			DP: no effect	[31, 35, 48, 59, 61, 78, 82, 99]
			AP: heavier	[13]f, g
			AP: no effect	[17, 95, 96]
Foetal weight	2/10	Weak	DP: heavier	[28i, 99]	–
			DP: no effect	[31, 35, 59, 61, 83, 95]
			AP: no effect	[13g, 95, 96]
Maternal ethnicity	3/5	Conflicting	DP: Caucasian	[31]	–
			DP: Sephardic	[78]
			AP: Asian	[53]
			AP: no effect	[95, 96]
Maternal bone density	0/1	No	DP: no effect	[10]	–
Oral contraceptives	1/4	Weak	DP: no effect	[7, 11, 82]	–
			AP: short term use	[11]
Smoking	2/5	Weak	DP: yes	[7, 28]	Strenuous work [7]
			DP: no effect	[45, 48, 99]
Strenuous work	8/12	Strong	DP: yes	[7, 19, 28, 35, 82]	–
			DP: no effect	[15, 48]
			AP: yes	[15, 53, 81]
			AP: no effect	[19, 109]
Previous low back pain (in four of the studies related to menstruation)	12/18	Strong	DP: yes	[35, 45j, 48, 61, 78, 80, 82]	–
			DP: no effect	[7, 11, 45k, 61, 107]
			AP: yes	[11, 13, 81, 96, 109]
			AP: no effect	[17]
Previous lumbopelvic pain during or after pregnancy	11/12	Strong	DP: yes	[7, 11, 15, 23, 45j, 48, 78, 83]	–
			DP: no effect	[45k]
			AP: yes	[11, 15, 81]
Previous abortion	0/2	No	DP: no effect	[35, 78]	–
Epidural anaesthesia	2/11	Weak	DPc: no effect	[78]	–
			AP: yes	[53, 95]
			AP: no effect	[13g, 17, 43, 51, 52, 69, 96, 108]
Prolonged second stage of labour	1/5	Weak	AP: yes	[53]	Traumatic labour [63]
			AP: no effect	[13, 17, 95, 96]

^ax/y: x out of the y relevant studies revealed an association

^bTerms such as “older” identify the risk factor in question. Note that we focused on significance: an “effect” implies that a significant relationship was found, “no effect” that no significant relationship was found

^cRefers to subsequent pregnancy

^dFor the first and second pregnancies

^eFor the second pregnancy only

^fIncluding cases where “low back pain” had been present before or during pregnancy

^gExcluding such cases (cf., footnote f)

^hFor nulliparous women

ⁱA very small partial regression: r=0.0001

^jFor the continuation of pain that already existed

^kFor new-onset pain