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Insertion technique, not design, affects expulsion rates of postpartum intrauterine device
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enn [1] r e c e n t l v o u t l i n e d s e Woposed adv teges o f p o s t p t ins Lion o¢ i n t r refine d ices ( I s): f i r s t , de e ed p~tient disc f t because the c ix is elre o p e ~ second, e l i initiation oF c o n t r eptio~ d t h i r d , cont t with mediced f i l i t i e ~ that m n o t be ~I l e to the p~tient l a t e r , e s p e c i e l l v i n d e l o p i n g c o u n t r i e s . To t h e s e rages may be added the pres ~ l y i n eased m o t i v a t i o n o f p ~ i e ~ s t o accept c o n t r e p t i o n at t h e t i m e o f d e l i v y . H ev , p t p ~ t u m i n s L i o n oF I s has been sociated th higher r ~ e s o¢ e x p u l s i o n t h IUOs i n s t e d long aft ~egn cy [2, 3 ] . F thisre on, v i o u s m o d i f i c a t i o n s o f co entton:al I d e s i g n s h e been ex i n e d ¢ p tp um ins t i o n [ 1 ] . I n t h e present s t u o h y p o t h e s i s was t h a t the s p e c i r l c t e c h n i q u e used f p p u ins t l o n of a modified I would a f f e c t s u b s e q u e n t e x p u l s i o n r a t e s oF the d i c e . To t e s t t h i s h y p o t h e s l ~ a p r o s p e c t i v e , r d l z e d s t u d y o f two i n s t i o n t e c h n i q u e s was p f ed u s i n g t h e m o d i f i e d I f 1 ediete p p u ins tlon In heathy volunte s loll 1rig t vagI deltv . The d l c e we t e s t e d had c ~ i c sut e added t o t h e upp l i m b o~ a Lipp Loop I d we c p ed our e x p e r i e n c e t o e x p u l s i o n r a t e s r e p t e d by pc l o u s 1 e s t t g ~ s f stend d, u o d i ¢ i e d L i p p I s. *
to
.
er
Submitted for publication gust 2~, 1984 Accepted for publication September 19, 1984
OC
BER
19
V O L . 3 0 NO. 4
327
CONTRACEPTION MATERIALS Volunte s w ere uited ~ ongo n m~ ~enatal p~ients. All s u b j e c t s w e i n good h e a l t h , d pl ned t o use IUD f contraception. Hist of doc ented p e l v i c i n f e c t i o n , e c t o p i c pregn g e n i t a l malignan o r undiagnosed abn mall b l e e d i n g were s p e c i f i c e x c l u s i o n s f r eligibility. Inf ed consent was obt~ned pri to the onset of l~b f t h i s ~ o t o c o l eppr ed bv the I n t n s l R~i Bo d o f Pennsylv iaStateUniv s i t y S c h o o l of Hedicine st H e r s h ~ . o The t e s t e d I s w e st d d Lipp Loop d e v i c e s t o which t ~ e e s h o r t l e n g t h s or c ~ l c sut e had been a t t a c h e d at the upp m o f the device, desczibed elsewhere [4, 5 ] . These m o d i f i e d I s were ~ e p ed end ~ i ded i n s t e r i l e packaging by the Int natlon~ f e r t l l l t y Rese ch ogr underpermlsslon fz the Food and ug A ~ i n i s t r a t i o n . The st i l e packages w e not opened u n t i l the time of insertion. Rll subjects ~eceived i d e n t l c ~ I s but were rand l y assigned to h e the I inserted eith digitelly using a f ceps inserter. All d~lces w e lnse~ted within tenminutes toll l n g d e l i v e r y o f the p l en~a, except for fo s u b j e c t s (two i n each group) who had i n s ~ t i o n between ten m i n u t e s and two ho s ~ t del l v e r y . Subjects w e s l u a t e d i n the e IV postp t period_, d then at one month, t ee months d s i x months ter insertion. In ~ditio~. ~1 subjects w e i n s t r u c t e d t o c o n t a c t the i estigat s f health probl s t h a t occ r e d between scheduled v i s i t s . Statistical ~ y s l s was performed u s i n g t w o - t a i l e d S t u d e n t ' s t - t e s t , or Chi-Squ e t e s t , as ~ p r o p r i ~ e . A l l data e presented as me +_ s t d d e~or o f t he me ( ), unl e ss ot herwi se not e d. SULTS
Of o 114 subjects, 59 received I ins tion digitally, and 55 recelve~ ins t l o n uslfig the l n s tar lnstr ant. T I bel des l b e s the d ogr h i c ch s c t e r i s t i c s o f these two ~ o u p s . The ~ o u p s were s t a t i s t i c ~ l y I n d i s t i n g u i s h a b l e in age, e d u c t i o n , d p ity. T
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¢HRR~~HISTZ':T. Rge ( y e
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ity
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p i~ly 25.5 ~ 0.72
s)
13.850.37 1.~J ~ 0 . 1 2
P
e
.4 ± 0.65
1 2 . 6 ÷_0.08 1.8~0.12
T ZZ bel esents t h e d e t a i l e d e x p e r i e n c e o f both ~ o u p s i n r a t e s of ~egn cies, e x p u l s i o n ~ r als d c o n t i n u a t i o n s . Rt s i x month~, ~e loll up r a t e o f 74.4% was achi ed, ~ o u t e q u ~ i n b o t h cups. F b o t h ~ o u p s , t h e e x p u l s i o n r a t e s w e high, d w e statistically (p
328
OC
BER 1984 VOL. 3 0 NO. 4
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w i t h f+ .
: +
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e g n a n c l es Expulsion~ R ovals (Pain lead) R a l s ( Q t he~ ) Cont i nuat i one
ceps (48.3~¢).
=++ :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
+:...... E f r e c t l v e n e m s
ION
and C o n t i n u a t i o n
6.0 ~ 0.41 19.5 ~0.56 1.9±0.12 4 . 5 +__0 . 3 2 68.1
......................................................................................................................
Rates (~) of Study
0 . 0 ~_0 . 0 39.6 ~0.71
cup=
< 0.05
5.7+_0.41 10.2 + 0.56 48.3
<0.05
D ing the stu whenthe f i r s t 47 insertions had been r i cO, we found t h a t the r i s k o f l ~ e r e x p u l s i o n was c l e l y r e l a t e d t o the exp i e n c e of" the p son p f ing the insertion. Only one out of 12 insertions p f ed by attending faculty w Poll ed by l ~ expulsion, whereas 20 out of ~5 ins tions by the ~ e s i d e n t s t a f f ~ e s u l t e d i n e x p u l s i o n a s t a t i s t i c ~ diP~ ence a t p
I
Th e e cle a~ tages i n c o n t r a c e p t i v e m ag ant t o be g a i n e d i f I s could be i n s ted postp t , presL~ing r e s u l t s w e c ~ l e to I s inserted i n t e ~ e l l y between egn~cies [1, 4]. With this ~~. modi£ied I s hm~e been d eloped d tested in att pt t o c i r c ent the kn n d i f f i c u l t i e s associated with post~egn ins tion, most imp t t l y incre ed expulsion rates, d de eased c o n t i n u a t i o n r a t e s [ 4 ] . In thi~ =tu we tested one such modified device, ad ration of the LIpp Loop. Other i estig~ s h e suggested t h a t I s ins ted v e ly (that is, minutes ho s ? o l l ing d e l i v ) h better outc e th thoseins ted days after deliv [ 1 ) . A l l i n s e r t i o n s i n the ~ e s e n t stuch/w e p £ ed l e s s t h two ho s a f t deliv o¢ the pl ent~ with 9 acc plished within ten minutes of placent~ deliv .0 data l n d i c a t e t h a t en t h i s v y e l y i n s e r t i o n time i s st i l I associated wi th hi gh expulsion r a t e s . In o s t u d y , expulsion rates f t h i s modified d ice w e no better th the rates ~ iously rep ted by oth s using st d d IUDs ins ted postp t [2, 3]. We did not c p e st d d I s i n the esent study. 0 data confi therep ts of other i estigat s that ch gas in the IUD design do not se t o s i g n i t i c t l y a f f e c t outc e o f t h e d ice [5]. We did Find that postp t I s ins ted d i g i t a l l y had e hlQh continuation rate th I s ins ted with a f c e ~ ins t i o n i n s t r ent. I t se s reason~le t h ~ d i g i t a l ins t i o n ~ l sm el edi~e dobJectiveconfl etlon of the rec endadhigh fundal p l ent of the d ice, d thus de e e~ expulslon
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VOL. 3 0 NO. 4
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CONTRACE
ION
~ a t e s b y thismech
i . Rn a d d i t i o n e / f t which a f f e c t e d the c o n t i n u ~ i o n r ~ e s f the modified I we tested w the i el of s k i l l , tzaining and exp ience of the individucl p ? ing the ins tion. Th ew acle s t ~ I s t i c ~ l y signific t d i f f ence between the expulsion ~ates of d ices Ins ted by attending s t a f f c p ed t o ~esident p h y s i c t s. F t e. t ~ ~ n t n g sessions s i g n i f t c tly de • ed the e x p u l s i o n ~ates f I s s u b s e q u e n t l y l n s e ~ t e d . I t has been ~epo~ted t h a t e x p u l s i o n ~ates de e e w i t h c o n t i n u i n g exp ienc~, en when a s i n g l e skilled individual p f s a l l the i n s t i o n s using a s i n g l e t e c h n i q u e [ 1 ] . I n o =tu d i s t r i b u t i o n of digite~l Inst~ ent ins tions was ~ d betweenthe I s ins ted by ~tendings, d those i n s t e d by ~esidents. suggesting t h ~ the two e f f e c t s ( t n s t ~ entation d s k i l l ) so t o be independent. Fr this inf m~lon, we conclude- first, that thls modlfic~ion of ¢ st d d I de¢ign o f f s noreal a tages f postp t ins tion, ~ least in t s o f e x p u l s i o n and c o n t i n u a t i o n r a t e s ; d second, the t e c h n i q u e used f postp t ins tion c signific tly imp t upon expulsion d continu~ion r a t e s , pros a b l y because o f d i f f e r e n c e s i n llity to achl e d c o n f i r m high funde/ pl ent of the I . Both d t f f ent I n s t r ents f ins tion, d dirt ent 1 e l s o f s k i l l In p sonnel, e d o n s t r a t e d to be c ponents of t h i s i n s t i on t e c h n i q u e e f f e c t . We e g r a t e f u l t o the I n t e x n a t l o n e l F t l l l t y Rese ch o~~ (F i l y H e a t h I n t n~ion~), e s p e o i ~ l y Ms Susan MoInt e end HsCynthiaWaszak, f pc l d l n g the d lees, df thelr support.
1. i
enn , P.F. R c l i n i c e / t r i ~ o f the D e l t T i n t r t ine d icee d i a t e postp t i n s t i o n . Contr e p t i o n 28:135-147 (1983).
2. H ~ b t, D.R., C ~ i s t ~ o s , A.C. d L ¢ V.B. Ins t i o n o f the Lippes Loop I n the 1 e d l ~ e postp t patlent- c p lson wlth 1~ i n s t l o n s . South n Med 3 64-707-710 (1971).
3. Ph~ed% L.V. d B h a t i ~ M. Obs v a t i o n s on e x p u l s i o n o f the I in pu p eL1 and nonpu p al i n s t i o n s . J 0 b s t e t Gvnecol 101-773-775
( lg6e).
4. L f ~ L . E . , Wheel d ices f postp
, R.G. t ins
d F r l e l , P.G. M o d i f i c a t i o n o f i n t r a u t t i o n . L cet i - 8 5 ~ 8 5 4 (1979).
ine
5. Ch poot eep, S., R e i n ~ ~ o o n , D., V i r u t en, P., S boonsuk, R. d D u s i t s l n , N. R c p a t i v e study o r Lippes Loop d D e l t a Loop i n t z u t i n e d i c e s i n e l y postp t . Contr e p t i o n 2 B - 3 9 ~ (1983).
330
R
1984 VOL. 30 NO. 4
I
RTI
TE
I
,
OF
TP
G. S t D
t
A Li: t
i . I i hi of
of
t t
I
.
I
M.D.*
LSI
M.
It
In
1~
i
ti
si
fi
RR
VI C.N.M. a
at
t
ti
RFFECTS
stty
ate
1
S
(
)
i
s :in
t i e d to be t
fi
iately aft ~i at six s1 r~ e si fi ly dt . ~ p(O. 1 t d i g i ~ a l l y ( 1 9 . 5 5 . 6 ~; a t 6 ) t usi gi ~ .1¢1. t f i i . i t :~ st l a i ~ g h ex
t
I
stetrics Ci
int i
l
ION
t i
t
Ii
ate l
i ely
t o t ho
t i t w
in
f
in
si -llthis 8i :~ i of,
e ~ si
i 2)t .
I
enn [1] r e c e n t l v o u t l i n e d s e Woposed adv teges o f p o s t p t ins Lion o¢ i n t r refine d ices ( I s): f i r s t , de e ed p~tient disc f t because the c ix is elre o p e ~ second, e l i initiation oF c o n t r eptio~ d t h i r d , cont t with mediced f i l i t i e ~ that m n o t be ~I l e to the p~tient l a t e r , e s p e c i e l l v i n d e l o p i n g c o u n t r i e s . To t h e s e rages may be added the pres ~ l y i n eased m o t i v a t i o n o f p ~ i e ~ s t o accept c o n t r e p t i o n at t h e t i m e o f d e l i v y . H ev , p t p ~ t u m i n s L i o n oF I s has been sociated th higher r ~ e s o¢ e x p u l s i o n t h IUOs i n s t e d long aft ~egn cy [2, 3 ] . F thisre on, v i o u s m o d i f i c a t i o n s o f co entton:al I d e s i g n s h e been ex i n e d ¢ p tp um ins t i o n [ 1 ] . I n t h e present s t u o h y p o t h e s i s was t h a t the s p e c i r l c t e c h n i q u e used f p p u ins t l o n of a modified I would a f f e c t s u b s e q u e n t e x p u l s i o n r a t e s oF the d i c e . To t e s t t h i s h y p o t h e s l ~ a p r o s p e c t i v e , r d l z e d s t u d y o f two i n s t i o n t e c h n i q u e s was p f ed u s i n g t h e m o d i f i e d I f 1 ediete p p u ins tlon In heathy volunte s loll 1rig t vagI deltv . The d l c e we t e s t e d had c ~ i c sut e added t o t h e upp l i m b o~ a Lipp Loop I d we c p ed our e x p e r i e n c e t o e x p u l s i o n r a t e s r e p t e d by pc l o u s 1 e s t t g ~ s f stend d, u o d i ¢ i e d L i p p I s. *
to
.
er
Submitted for publication gust 2~, 1984 Accepted for publication September 19, 1984
OC
BER
19
V O L . 3 0 NO. 4
327
CONTRACEPTION MATERIALS Volunte s w ere uited ~ ongo n m~ ~enatal p~ients. All s u b j e c t s w e i n good h e a l t h , d pl ned t o use IUD f contraception. Hist of doc ented p e l v i c i n f e c t i o n , e c t o p i c pregn g e n i t a l malignan o r undiagnosed abn mall b l e e d i n g were s p e c i f i c e x c l u s i o n s f r eligibility. Inf ed consent was obt~ned pri to the onset of l~b f t h i s ~ o t o c o l eppr ed bv the I n t n s l R~i Bo d o f Pennsylv iaStateUniv s i t y S c h o o l of Hedicine st H e r s h ~ . o The t e s t e d I s w e st d d Lipp Loop d e v i c e s t o which t ~ e e s h o r t l e n g t h s or c ~ l c sut e had been a t t a c h e d at the upp m o f the device, desczibed elsewhere [4, 5 ] . These m o d i f i e d I s were ~ e p ed end ~ i ded i n s t e r i l e packaging by the Int natlon~ f e r t l l l t y Rese ch ogr underpermlsslon fz the Food and ug A ~ i n i s t r a t i o n . The st i l e packages w e not opened u n t i l the time of insertion. Rll subjects ~eceived i d e n t l c ~ I s but were rand l y assigned to h e the I inserted eith digitelly using a f ceps inserter. All d~lces w e lnse~ted within tenminutes toll l n g d e l i v e r y o f the p l en~a, except for fo s u b j e c t s (two i n each group) who had i n s ~ t i o n between ten m i n u t e s and two ho s ~ t del l v e r y . Subjects w e s l u a t e d i n the e IV postp t period_, d then at one month, t ee months d s i x months ter insertion. In ~ditio~. ~1 subjects w e i n s t r u c t e d t o c o n t a c t the i estigat s f health probl s t h a t occ r e d between scheduled v i s i t s . Statistical ~ y s l s was performed u s i n g t w o - t a i l e d S t u d e n t ' s t - t e s t , or Chi-Squ e t e s t , as ~ p r o p r i ~ e . A l l data e presented as me +_ s t d d e~or o f t he me ( ), unl e ss ot herwi se not e d. SULTS
Of o 114 subjects, 59 received I ins tion digitally, and 55 recelve~ ins t l o n uslfig the l n s tar lnstr ant. T I bel des l b e s the d ogr h i c ch s c t e r i s t i c s o f these two ~ o u p s . The ~ o u p s were s t a t i s t i c ~ l y I n d i s t i n g u i s h a b l e in age, e d u c t i o n , d p ity. T
I~
b~o
~ Ji,:: ':;h
¢HRR~~HISTZ':T. Rge ( y e
s;
Education (ye P
ity
act eristi
cs o f Study
cups
NT
p i~ly 25.5 ~ 0.72
s)
13.850.37 1.~J ~ 0 . 1 2
P
e
.4 ± 0.65
1 2 . 6 ÷_0.08 1.8~0.12
T ZZ bel esents t h e d e t a i l e d e x p e r i e n c e o f both ~ o u p s i n r a t e s of ~egn cies, e x p u l s i o n ~ r als d c o n t i n u a t i o n s . Rt s i x month~, ~e loll up r a t e o f 74.4% was achi ed, ~ o u t e q u ~ i n b o t h cups. F b o t h ~ o u p s , t h e e x p u l s i o n r a t e s w e high, d w e statistically (p
328
OC
BER 1984 VOL. 3 0 NO. 4
CONTRACE (6+8.1~) ~ ~ h e r t h .
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L+~+
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w i t h f+ .
: +
+~+
e g n a n c l es Expulsion~ R ovals (Pain lead) R a l s ( Q t he~ ) Cont i nuat i one
ceps (48.3~¢).
=++ :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
+:...... E f r e c t l v e n e m s
ION
and C o n t i n u a t i o n
6.0 ~ 0.41 19.5 ~0.56 1.9±0.12 4 . 5 +__0 . 3 2 68.1
......................................................................................................................
Rates (~) of Study
0 . 0 ~_0 . 0 39.6 ~0.71
cup=
< 0.05
5.7+_0.41 10.2 + 0.56 48.3
<0.05
D ing the stu whenthe f i r s t 47 insertions had been r i cO, we found t h a t the r i s k o f l ~ e r e x p u l s i o n was c l e l y r e l a t e d t o the exp i e n c e of" the p son p f ing the insertion. Only one out of 12 insertions p f ed by attending faculty w Poll ed by l ~ expulsion, whereas 20 out of ~5 ins tions by the ~ e s i d e n t s t a f f ~ e s u l t e d i n e x p u l s i o n a s t a t i s t i c ~ diP~ ence a t p
I
Th e e cle a~ tages i n c o n t r a c e p t i v e m ag ant t o be g a i n e d i f I s could be i n s ted postp t , presL~ing r e s u l t s w e c ~ l e to I s inserted i n t e ~ e l l y between egn~cies [1, 4]. With this ~~. modi£ied I s hm~e been d eloped d tested in att pt t o c i r c ent the kn n d i f f i c u l t i e s associated with post~egn ins tion, most imp t t l y incre ed expulsion rates, d de eased c o n t i n u a t i o n r a t e s [ 4 ] . In thi~ =tu we tested one such modified device, ad ration of the LIpp Loop. Other i estig~ s h e suggested t h a t I s ins ted v e ly (that is, minutes ho s ? o l l ing d e l i v ) h better outc e th thoseins ted days after deliv [ 1 ) . A l l i n s e r t i o n s i n the ~ e s e n t stuch/w e p £ ed l e s s t h two ho s a f t deliv o¢ the pl ent~ with 9 acc plished within ten minutes of placent~ deliv .0 data l n d i c a t e t h a t en t h i s v y e l y i n s e r t i o n time i s st i l I associated wi th hi gh expulsion r a t e s . In o s t u d y , expulsion rates f t h i s modified d ice w e no better th the rates ~ iously rep ted by oth s using st d d IUDs ins ted postp t [2, 3]. We did not c p e st d d I s i n the esent study. 0 data confi therep ts of other i estigat s that ch gas in the IUD design do not se t o s i g n i t i c t l y a f f e c t outc e o f t h e d ice [5]. We did Find that postp t I s ins ted d i g i t a l l y had e hlQh continuation rate th I s ins ted with a f c e ~ ins t i o n i n s t r ent. I t se s reason~le t h ~ d i g i t a l ins t i o n ~ l sm el edi~e dobJectiveconfl etlon of the rec endadhigh fundal p l ent of the d ice, d thus de e e~ expulslon
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i . Rn a d d i t i o n e / f t which a f f e c t e d the c o n t i n u ~ i o n r ~ e s f the modified I we tested w the i el of s k i l l , tzaining and exp ience of the individucl p ? ing the ins tion. Th ew acle s t ~ I s t i c ~ l y signific t d i f f ence between the expulsion ~ates of d ices Ins ted by attending s t a f f c p ed t o ~esident p h y s i c t s. F t e. t ~ ~ n t n g sessions s i g n i f t c tly de • ed the e x p u l s i o n ~ates f I s s u b s e q u e n t l y l n s e ~ t e d . I t has been ~epo~ted t h a t e x p u l s i o n ~ates de e e w i t h c o n t i n u i n g exp ienc~, en when a s i n g l e skilled individual p f s a l l the i n s t i o n s using a s i n g l e t e c h n i q u e [ 1 ] . I n o =tu d i s t r i b u t i o n of digite~l Inst~ ent ins tions was ~ d betweenthe I s ins ted by ~tendings, d those i n s t e d by ~esidents. suggesting t h ~ the two e f f e c t s ( t n s t ~ entation d s k i l l ) so t o be independent. Fr this inf m~lon, we conclude- first, that thls modlfic~ion of ¢ st d d I de¢ign o f f s noreal a tages f postp t ins tion, ~ least in t s o f e x p u l s i o n and c o n t i n u a t i o n r a t e s ; d second, the t e c h n i q u e used f postp t ins tion c signific tly imp t upon expulsion d continu~ion r a t e s , pros a b l y because o f d i f f e r e n c e s i n llity to achl e d c o n f i r m high funde/ pl ent of the I . Both d t f f ent I n s t r ents f ins tion, d dirt ent 1 e l s o f s k i l l In p sonnel, e d o n s t r a t e d to be c ponents of t h i s i n s t i on t e c h n i q u e e f f e c t . We e g r a t e f u l t o the I n t e x n a t l o n e l F t l l l t y Rese ch o~~ (F i l y H e a t h I n t n~ion~), e s p e o i ~ l y Ms Susan MoInt e end HsCynthiaWaszak, f pc l d l n g the d lees, df thelr support.
1. i
enn , P.F. R c l i n i c e / t r i ~ o f the D e l t T i n t r t ine d icee d i a t e postp t i n s t i o n . Contr e p t i o n 28:135-147 (1983).
2. H ~ b t, D.R., C ~ i s t ~ o s , A.C. d L ¢ V.B. Ins t i o n o f the Lippes Loop I n the 1 e d l ~ e postp t patlent- c p lson wlth 1~ i n s t l o n s . South n Med 3 64-707-710 (1971).
3. Ph~ed% L.V. d B h a t i ~ M. Obs v a t i o n s on e x p u l s i o n o f the I in pu p eL1 and nonpu p al i n s t i o n s . J 0 b s t e t Gvnecol 101-773-775
( lg6e).
4. L f ~ L . E . , Wheel d ices f postp
, R.G. t ins
d F r l e l , P.G. M o d i f i c a t i o n o f i n t r a u t t i o n . L cet i - 8 5 ~ 8 5 4 (1979).
ine
5. Ch poot eep, S., R e i n ~ ~ o o n , D., V i r u t en, P., S boonsuk, R. d D u s i t s l n , N. R c p a t i v e study o r Lippes Loop d D e l t a Loop i n t z u t i n e d i c e s i n e l y postp t . Contr e p t i o n 2 B - 3 9 ~ (1983).
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