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Temporal trends in multiple births after in vitro fertilisation in
Papers 7 Albaum MN, Hill LC, Murphy M, Li YH, Fuhrman CR, Britton CA, et al. 11 Tudor GR, Finlay DB. Error review: can this improve reporting perform- Interobserver reliability of the chest radiograph in community-acquired ance? Clin Radiol 2001;56:751-4. pneumonia. PORT Investigators. Chest 1996;110:343-50. 12 Kwong JS, Carignan S, Kang EY, Muller NL, FitzGerald JM. Miliary tuber- 8 Alland D, Kalkut GE, Moss AR, McAdam RA, Hahn JA, Bosworth W, et al. culosis. Diagnostic accuracy of chest radiography. Chest 1996;110:339-42. Transmission of tuberculosis in New York city. An analysis by DNA 13 Dhingsa R, Finlay DB, Robinson GD, Liddicoat AJ. Assessment of agree- fingerprinting and conventional epidemiologic methods. N Engl J Med ment between general practitioners and radiologists as to whether a 1994;330:1710-6. radiation exposure is justified. Br J Radiol 2002;75:136-9. 9 Coblentz CL, Babcook CJ, Alton D, Riley BJ, Norman G. Observer varia- 14 Zitting AJ. Prevalence of radiographic small lung opacities and pleural tion in detecting the radiologic features associated with bronchiolitis. abnormalities in a representative adult population sample. Chest Invest Radiol 1991;26:115-8. 1995;107:126-31. 10 Du Toit G, Swingler G, Iloni K. Observer variation in detecting lymphad- enopathy on chest radiography. Int J Tuberc Lung Dis 2002;6:814-7. (Accepted 22 June 2005) Temporal trends in multiple births after in vitro fertilisation in Sweden, 1982-2001: a register study Bengt Källén, Orvar Finnström, Karl Gösta Nygren, Petra Otterblad Olausson Centre for During the 20 years since the first child was born in Reproduction Sweden after in vitro fertilisation, clinical policy has What is already known on this topic Epidemiology, Tornblad Institute, changed. During the early 1990s, the clinics perform- Pregnancies occurring after in vitro fertilisation University of Lund, ing in vitro fertilisation and the National Board of Biskopsgatan 7, are characterised by high rates of multiple births S-223 62 Lund, Health and Welfare agreed to reduce the number of and, as a consequence, high rates of preterm Sweden embryos transferred to the uterus during in vitro ferti- births Bengt Källén lisation from three to two. Here, we describe the professor changes in multiple birth rates that have resulted from During the 1990s Swedish fertility clinics agreed Department of this change and their impact on the rate of preterm to reduce from three to two the number of Paediatrics, University Hospital, birth. In future papers we intend to describe maternal embryos transferred to the uterus during in vitro S-581 85 and child characteristics in greater detail. fertilisation Linköping, Sweden Orvar Finnström What this study adds professor Participants, methods, and results IVF Clinic, The rate of multiple births after in vitro Sophiahemmet, In Sweden 17 hospitals or private clinics perform in fertilisation increased to a maximum of 29% in S-114 86 vitro fertilisation. The National Board of Health and 1991 but fell to 18.5% by 2001, resulting in a 70% Stockholm, Sweden Welfare requested information from these laboratories reduction of preterm births Karl Gösta Nygren on all women who had undergone in vitro fertilisation associate professor and who had had a baby or whose pregnancy outcome Centre for Epidemiology, was not known. By linking these data with the Swedish born in Sweden and recorded in that registry National Board of medical birth register, we identified infants born from (2 039 943 during 1982-2001). We performed statisti- Health and Welfare, 1982 to 2001.1 2 This register covers nearly all deliver- cal analyses using the Mantel-Haenszel technique, with Stockholm, Sweden ies in Sweden and is based on copies of medical docu- adjustment for various putative confounders. We Petra Otterblad Olausson ments from the antenatal care, the delivery, and the expressed risks as odds ratios and calculated 95% con- head of register paediatric examination of newborn infants. fidence intervals with a test-based method (according Correspondence to: We compared the infants born after in vitro fertili- to Miettinen). Bengt Källén sation and identified in the registry with all infants embryol@ We studied a total of 13 261 births after in vitro fer- embryol.lu.se tilisation, which resulted in 16 280 infants registered. 35 Twin deliveries (%) The figure shows the changes in percentage of twin BMJ 2005;331:382–3 30 deliveries according to year of birth, with the first seven years added because of low numbers. The twinning 25 rate increased to a maximum of 29% in 1991 and then 20 decreased steadily to 18.5% in 2001. The annual number of triplet deliveries after in vitro fertilisation 15 varied between 11 and 32 during 1992-6, and between 10 three and seven after 1997. All seven sets of quadruplets were born before 1994. 5 The impact of the reduction of multiple births on 0 the rate of preterm births is marked. In 1991, the crude 1988 89 90 91 92 93 94 95 96 97 98 99 2000 01 odds ratio for preterm birth was 9.41 (95% confidence Year of birth interval 7.58 to 11.67) and the odds ratio adjusted for maternal age (in 5 year groups, < 20, 20-24, etc), parity Changes in percentage of deliveries after in vitro fertilisation that resulted in birth of twins, by year of birth (vertical bars are 95% confidence intervals) This article was posted on bmj.com on 13 May 2005: http://bmj.com/cgi/ doi/10.1136/bmj.38443.595046.E0 382 BMJ VOLUME 331 13 AUGUST 2005 bmj.com Papers (1- ≥ 4), smoking (none, < 10, ≥ 10 cigarettes/day), and to one, and a further reduction in multiple births is to years of involuntary childlessness was 4.63 (3.62 to be expected whereas the pregnancy rate seems to be 5.92). The corresponding odds ratios in 2001 were 2.15 little affected.4 5 (1.76 to 2.62) and 1.33 (1.12 to 1.57). The risk for pre- Contributors: BK planned the study, analysed the data, and term birth after in vitro fertilisation was thus reduced wrote the first manuscript draft. OF and KGN planned the by 77% (crude odds ratio) and 72% (adjusted odds study, helped in interpreting the data, and helped finalise the ratio). manuscript. POO planned the study, collected data, helped in interpreting the data, and helped finalise the manuscript. BK is guarantor for the study. Comment Funding: Grant from K and A Wallenberg Foundation (BK). Competing interests: None declared. The rate of high order multiple births after in vitro fer- Ethical approval: Not required. tilisation declined markedly during the 1991-2001, and the twinning rate decreased by about 40% from a 1 Cnattingius S, Ericson A, Gunnarskog J, Källén B. A quality study of a maximum of 29% in 1991 to 18.5% in 2001. At the medical birth registry. Scand J Soc Med 1990;18:143-8. 2 Centre for Epidemiology, Swedish National Board of Health and Welfare. same time, the population twinning rate increased. The The Swedish Medical Birth Registry—a summary of content and quality. Stock- European twinning rate after in vitro fertilisation was holm: Swedish National Board of Health and Welfare, 2003. (www.sos.se/ FULLTEXT/112/2003-112-3/2003-112-3.pdf) 24.4% in 2000.3 The declining rate of multiple births 3 Assisted reproductive technology in Europe, 2000. Results generated affected the risk of preterm infants, which declined by from European registers by ESHRE. Hum Reprod 2004;19:490-503. 4 Tiitinen A, Unkilakallio L, Halttunen M, Hydén-Granskog C. Impact of over 70%, and improved neonatal outcome. elective single embryo transfer on the twin pregnancy rate. Hum Reprod The change in clinical policy in the early 1990s that 2003;18:1449-53. 5 Thurin A, Hausken J, Hillensjö T, Jablonowska B, Pinborg A, Strandell A, initiated these changes was reducing from three to two et al. Elective single-embryo transfer versus double-embryo transfer in in the number of embryos transferred to the uterus dur- vitro fertilization. N Engl J Med 2004;351:2392-402. ing in vitro fertilisation. At present, the number of (Accepted 31 March 2005) embryos transferred is being reduced further, from two doi 10.1136/bmj.38443.595046.E0 When I use a word . . . Rabid responses At last the BMJ has realised that too many rapid LABH, by another consonantal shift, became RABH, responses are actually rabid responses (BMJ which gave the Greek word ereptomai, “to feed,” 2005;330:1284). But Grimm’s law predicts it. related to ereptein (Latin eripere), “to pluck.” Erepsin The brothers Grimm, Jakob Ludwig and Wilhelm was the name that Otto Cohnheim used in 1901, Karl, are best known for the collection of fairy tales presumably surreptitiously, to describe a group of that bears their name, first published in two volumes in polypeptidases found in the small intestine. The name 1812 and 1814 under the title Kinder- und came from ereptomai plus pepsin. Hausmärchen, with a third volume added in 1822. The RABH also gave the Latin word rabere or, by tales have enthralled children ever since, but the Grimm’s law, rapere, “to seize.” Whence the English brothers collected them as an act of serious words rabies, rabid, rape, raptor, rapture, and rapid. scholarship, consulting mediaeval manuscripts and Rabies is the Latin word for fury or madness, because talking to villagers and peasants in the districts of it seizes your mind. In France, by another consonantal Hesse and Hanau and transcribing their tales. shift, it is called la rage. The disease has also been The brothers were also eminent philologists, and called lyssa, the Greek word for madness, which Jakob’s work is commemorated in Grimm’s law. That it is called Grimm’s law confirms another law, that of Homer used to describe battle rage, but which later Non-Original Malappropriate Eponymous authors used to refer to other forms, such as Bacchic Nomenclature (NOMEN), which states that no frenzy, the frenzy of the Furies, and even passionate phenomenon is named after its discoverer. The love, before applying it to rabies in dogs. principles of Grimm’s law were first described by Ravenous, ravish, and reverie (which originally Friedrich von Schlegel in 1806 and the Danish meant delirium) also come from RABH, via yet philologist Rasmus Kristian Rask in 1818; Jakob another consonantal shift, this time Verner’s law, after Grimm discussed them in detail in 1822 in his book the Danish philologist who described it (preceded by Deutsche Grammatik. Grassman). Henry Fielding well understood how rapid Grimm’s law is complicated, but it governs the ways ravishment could be. “Fireblood,” he wrote in Jonathan in which particular sets of consonants change from Wild (1743), “who was no backward Youth, began to one to another as languages develop. The relevant take [Loetitia] by the Hand, and proceeded so warmly, letter sets are the labials p, b, and f; the velars k, g, and that, to imitate his Actions with the Rapidity of our h; and the dentals t, d, and th. This explains the Narration, he in a few Minutes ravished this fair Latin-English and Greek-English correspondences of Creature, or at least would have ravished her, if she had pes-foot, labia-lip, and fundamentum-bottom (labials); not, by a timely Compliance, prevented him.” cardia-heart, genu-knee, and hostis-guest (velars); and So, the next time you are moved to write a rapid tres-three, duo-two, and thyroid-door (dentals). It also response, make sure that it’s not so rapid that it explains the association between rapid and rabid. becomes a rabid response instead and gets turned The Indo-European root LABH gave the Greeks down by the editors. lambanein (future lçpsomai), “to seize,” from which we get analeptic, cataleptic, epileptic, narcoleptic, and Jeff Aronson clinical pharmacologist, Oxford nympholeptic. And a syllable is letters taken together. (firstname.lastname@example.org) BMJ VOLUME 331 13 AUGUST 2005 bmj.com 383
"Temporal trends in multiple births after in vitro fertilisation in"